[RFC,v2,8/9] drm: writeback: Add out-fences for writeback connectors
Commit Message
Add the OUT_FENCE_PTR property to writeback connectors, to enable
userspace to get a fence which will signal once the writeback is
complete.
A timeline is added to drm_connector for use by the writeback
out-fences. It is up to drivers to check for a fence in the
connector_state and signal the it appropriately when their writeback has
finished.
It is not allowed to request an out-fence without a framebuffer attached
to the connector.
Signed-off-by: Brian Starkey <brian.starkey@arm.com>
---
drivers/gpu/drm/drm_atomic.c | 60 +++++++++++++++++++++++---
drivers/gpu/drm/drm_atomic_helper.c | 5 ++-
drivers/gpu/drm/drm_writeback.c | 80 +++++++++++++++++++++++++++++++++++
include/drm/drm_connector.h | 14 ++++++
include/drm/drm_writeback.h | 2 +
5 files changed, 155 insertions(+), 6 deletions(-)
Comments
On Wed, Oct 26, 2016 at 09:55:07AM +0100, Brian Starkey wrote:
> Add the OUT_FENCE_PTR property to writeback connectors, to enable
> userspace to get a fence which will signal once the writeback is
> complete.
>
> A timeline is added to drm_connector for use by the writeback
> out-fences. It is up to drivers to check for a fence in the
> connector_state and signal the it appropriately when their writeback has
> finished.
>
> It is not allowed to request an out-fence without a framebuffer attached
> to the connector.
>
> Signed-off-by: Brian Starkey <brian.starkey@arm.com>
Ah, here it is, so much for reading patches strictly in-order ;-) One
small comment below, otherwise I think this looks good. Again review from
Gustavo for the out fences stuff would be really good (so pls cc him). And
I think some igt testcases to exercise all the corner-cases in here.
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index a5e3778..7d40537 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -199,6 +199,7 @@ int drm_display_info_set_bus_formats(struct drm_display_info *info,
> * @best_encoder: can be used by helpers and drivers to select the encoder
> * @state: backpointer to global drm_atomic_state
> * @fb: Writeback framebuffer, for DRM_MODE_CONNECTOR_WRITEBACK
> + * @out_fence: Fence which will clear when the framebuffer write has finished
> */
> struct drm_connector_state {
> struct drm_connector *connector;
> @@ -216,6 +217,9 @@ struct drm_connector_state {
> struct drm_atomic_state *state;
>
> struct drm_framebuffer *fb; /* do not write directly, use drm_atomic_set_fb_for_connector() */
btw if you feel like adding a 2nd comment in-line like above, then that's
a clear signal that you should move your kerneldoc struct member comments
to the inline style. You can freely mix&match inline with top-level struct
member documentation, so no need to change them all. You also missed the
doc for out_fence_ptr, 0day won't like that.
> +
> + struct fence *out_fence;
> + u64 __user *out_fence_ptr;
writeback_ prefix for both imo, like in patch 1.
> };
>
> /**
> @@ -546,6 +550,10 @@ struct drm_cmdline_mode {
> * @tile_v_loc: vertical location of this tile
> * @tile_h_size: horizontal size of this tile.
> * @tile_v_size: vertical size of this tile.
> + * @fence_context: context for fence signalling
> + * @fence_lock: fence lock for the fence context
> + * @fence_seqno: seqno variable to create fences
> + * @timeline_name: fence timeline name
> *
> * Each connector may be connected to one or more CRTCs, or may be clonable by
> * another connector if they can share a CRTC. Each connector also has a specific
> @@ -694,6 +702,12 @@ struct drm_connector {
> uint8_t num_h_tile, num_v_tile;
> uint8_t tile_h_loc, tile_v_loc;
> uint16_t tile_h_size, tile_v_size;
> +
> + /* fence timelines info for DRM out-fences */
> + unsigned int fence_context;
> + spinlock_t fence_lock;
> + unsigned long fence_seqno;
> + char timeline_name[32];
Should all have writeout_ prefix. And at that point I wonder a bit whether
we shouldn't just go ahead and create a struct drm_writeout_connector, to
keep this stuff nicely separate. Only change visible to drivers would be
the type of drm_writeback_connector_init, and they'd need to
allocate/embedd a different struct. Worth it imo.
-Daniel
> };
>
> #define obj_to_connector(x) container_of(x, struct drm_connector, base)
> diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
> index afdc2742..01f33bc 100644
> --- a/include/drm/drm_writeback.h
> +++ b/include/drm/drm_writeback.h
> @@ -16,4 +16,6 @@ int drm_writeback_connector_init(struct drm_device *dev,
> const struct drm_connector_funcs *funcs,
> u32 *formats, int n_formats);
>
> +struct fence *drm_writeback_get_out_fence(struct drm_connector *connector,
> + struct drm_connector_state *conn_state);
> #endif
> --
> 1.7.9.5
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
Hi Gustavo,
It would be great if you could cast your eye over this one as-well.
My intention was to be as similar to the CRTC out-fences as possible.
Thanks,
Brian
On Wed, Oct 26, 2016 at 09:55:07AM +0100, Brian Starkey wrote:
>Add the OUT_FENCE_PTR property to writeback connectors, to enable
>userspace to get a fence which will signal once the writeback is
>complete.
>
>A timeline is added to drm_connector for use by the writeback
>out-fences. It is up to drivers to check for a fence in the
>connector_state and signal the it appropriately when their writeback has
>finished.
>
>It is not allowed to request an out-fence without a framebuffer attached
>to the connector.
>
>Signed-off-by: Brian Starkey <brian.starkey@arm.com>
>---
> drivers/gpu/drm/drm_atomic.c | 60 +++++++++++++++++++++++---
> drivers/gpu/drm/drm_atomic_helper.c | 5 ++-
> drivers/gpu/drm/drm_writeback.c | 80 +++++++++++++++++++++++++++++++++++
> include/drm/drm_connector.h | 14 ++++++
> include/drm/drm_writeback.h | 2 +
> 5 files changed, 155 insertions(+), 6 deletions(-)
>
>diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
>index 3f8fc97..061ea13 100644
>--- a/drivers/gpu/drm/drm_atomic.c
>+++ b/drivers/gpu/drm/drm_atomic.c
>@@ -30,6 +30,7 @@
> #include <drm/drm_atomic.h>
> #include <drm/drm_mode.h>
> #include <drm/drm_plane_helper.h>
>+#include <drm/drm_writeback.h>
> #include <linux/sync_file.h>
>
> #include "drm_crtc_internal.h"
>@@ -646,6 +647,12 @@ static int drm_atomic_connector_check(struct drm_connector *connector,
> return -EINVAL;
> }
>
>+ if (state->out_fence && !state->fb) {
>+ DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] requesting out-fence without framebuffer\n",
>+ connector->base.id, connector->name);
>+ return -EINVAL;
>+ }
>+
> return 0;
> }
>
>@@ -1047,6 +1054,8 @@ int drm_atomic_connector_set_property(struct drm_connector *connector,
> drm_atomic_set_fb_for_connector(state, fb);
> if (fb)
> drm_framebuffer_unreference(fb);
>+ } else if (property == config->prop_out_fence_ptr) {
>+ state->out_fence_ptr = u64_to_user_ptr(val);
> } else if (connector->funcs->atomic_set_property) {
> return connector->funcs->atomic_set_property(connector,
> state, property, val);
>@@ -1088,6 +1097,8 @@ drm_atomic_connector_get_property(struct drm_connector *connector,
> } else if (property == config->writeback_fb_id_property) {
> /* Writeback framebuffer is one-shot, write and forget */
> *val = 0;
>+ } else if (property == config->prop_out_fence_ptr) {
>+ *val = 0;
> } else if (connector->funcs->atomic_get_property) {
> return connector->funcs->atomic_get_property(connector,
> state, property, val);
>@@ -1736,6 +1747,39 @@ static int setup_out_fence(struct drm_out_fence_state *fence_state,
> return 0;
> }
>
>+static int setup_connector_out_fences(struct drm_atomic_state *state,
>+ struct drm_out_fence_state *fence_state,
>+ int *fence_idx)
>+{
>+ struct drm_connector *conn;
>+ struct drm_connector_state *conn_state;
>+ int i, ret;
>+
>+ for_each_connector_in_state(state, conn, conn_state, i) {
>+ struct fence *fence;
>+
>+ if (!conn_state->out_fence_ptr)
>+ continue;
>+
>+ fence = drm_writeback_get_out_fence(conn, conn_state);
>+ if (!fence)
>+ return -ENOMEM;
>+
>+ ret = setup_out_fence(&fence_state[(*fence_idx)++],
>+ conn_state->out_fence_ptr,
>+ fence);
>+ if (ret) {
>+ fence_put(fence);
>+ return ret;
>+ }
>+
>+ /* One-time usage only */
>+ conn_state->out_fence_ptr = NULL;
>+ }
>+
>+ return 0;
>+}
>+
> int drm_mode_atomic_ioctl(struct drm_device *dev,
> void *data, struct drm_file *file_priv)
> {
>@@ -1868,8 +1912,8 @@ retry:
> drm_mode_object_unreference(obj);
> }
>
>- fence_state = kcalloc(dev->mode_config.num_crtc, sizeof(*fence_state),
>- GFP_KERNEL);
>+ fence_state = kcalloc(dev->mode_config.num_crtc + state->num_connector,
>+ sizeof(*fence_state), GFP_KERNEL);
> if (!fence_state) {
> ret = -ENOMEM;
> goto out;
>@@ -1929,10 +1973,16 @@ retry:
> * Below we call drm_atomic_state_free for it.
> */
> ret = drm_atomic_check_only(state);
>- } else if (arg->flags & DRM_MODE_ATOMIC_NONBLOCK) {
>- ret = drm_atomic_nonblocking_commit(state);
> } else {
>- ret = drm_atomic_commit(state);
>+ ret = setup_connector_out_fences(state, fence_state,
>+ &fence_idx);
>+ if (ret)
>+ goto out;
>+
>+ if (arg->flags & DRM_MODE_ATOMIC_NONBLOCK)
>+ ret = drm_atomic_nonblocking_commit(state);
>+ else
>+ ret = drm_atomic_commit(state);
> }
>
> if (!ret)
>diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
>index bba8672..88da299 100644
>--- a/drivers/gpu/drm/drm_atomic_helper.c
>+++ b/drivers/gpu/drm/drm_atomic_helper.c
>@@ -3234,8 +3234,9 @@ __drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector,
> if (state->crtc)
> drm_connector_reference(connector);
>
>- /* Don't copy over framebuffers, they are used only once */
>+ /* Don't copy over framebuffers or fences, they are used only once */
> state->fb = NULL;
>+ state->out_fence = NULL;
> }
> EXPORT_SYMBOL(__drm_atomic_helper_connector_duplicate_state);
>
>@@ -3365,6 +3366,8 @@ __drm_atomic_helper_connector_destroy_state(struct drm_connector_state *state)
> drm_connector_unreference(state->connector);
> if (state->fb)
> drm_framebuffer_unreference(state->fb);
>+
>+ fence_put(state->out_fence);
> }
> EXPORT_SYMBOL(__drm_atomic_helper_connector_destroy_state);
>
>diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
>index 5a6e0ad..4a6ef30 100644
>--- a/drivers/gpu/drm/drm_writeback.c
>+++ b/drivers/gpu/drm/drm_writeback.c
>@@ -11,6 +11,7 @@
> #include <drm/drm_crtc.h>
> #include <drm/drm_property.h>
> #include <drm/drmP.h>
>+#include <linux/fence.h>
>
> /**
> * DOC: overview
>@@ -32,6 +33,16 @@
> * explicitly cleared in order to make a subsequent commit which doesn't use
> * writeback.
> *
>+ * Unlike with planes, when a writeback framebuffer is removed by userspace DRM
>+ * makes no attempt to remove it from active use by the connector. This is
>+ * because no method is provided to abort a writeback operation, and in any
>+ * case making a new commit whilst a writeback is ongoing is undefined (see
>+ * OUT_FENCE_PTR below). As soon as the current writeback is finished, the
>+ * framebuffer will automatically no longer be in active use. As it will also
>+ * have already been removed from the framebuffer list, there will be no way for
>+ * any userspace application to retrieve a reference to it in the intervening
>+ * period.
>+ *
> * Writeback connectors have several additional properties, which userspace
> * can use to query and control them:
> *
>@@ -52,8 +63,48 @@
> * "PIXEL_FORMATS_SIZE":
> * Immutable unsigned range property storing the number of entries in the
> * PIXEL_FORMATS array.
>+ *
>+ * "OUT_FENCE_PTR":
>+ * Userspace can provide the address of a 64-bit integer in this property,
>+ * which will be filled with a sync_file file descriptor by the kernel.
>+ * The sync_file will signal when the associated writeback has finished.
>+ * Userspace should wait for this fence to signal before making another
>+ * commit affecting any of the same CRTCs, Planes or Connectors.
>+ * **Failure to do so will result in undefined behaviour.**
>+ * For this reason it is strongly recommended that all userspace
>+ * applications making use of writeback connectors *always* retrieve an
>+ * out-fence for the commit and use it appropriately.
>+ * From userspace, this property will always read as zero.
> */
>
>+#define fence_to_connector(x) container_of(x->lock, struct drm_connector, fence_lock)
>+
>+static const char *drm_writeback_fence_get_driver_name(struct fence *fence)
>+{
>+ struct drm_connector *connector = fence_to_connector(fence);
>+
>+ return connector->dev->driver->name;
>+}
>+
>+static const char *drm_writeback_fence_get_timeline_name(struct fence *fence)
>+{
>+ struct drm_connector *connector = fence_to_connector(fence);
>+
>+ return connector->timeline_name;
>+}
>+
>+static bool drm_writeback_fence_enable_signaling(struct fence *fence)
>+{
>+ return true;
>+}
>+
>+static const struct fence_ops drm_writeback_fence_ops = {
>+ .get_driver_name = drm_writeback_fence_get_driver_name,
>+ .get_timeline_name = drm_writeback_fence_get_timeline_name,
>+ .enable_signaling = drm_writeback_fence_enable_signaling,
>+ .wait = fence_default_wait,
>+};
>+
> /**
> * create_writeback_properties - Create writeback connector-specific properties
> * @dev: DRM device
>@@ -136,6 +187,14 @@ int drm_writeback_connector_init(struct drm_device *dev,
> if (ret)
> goto fail;
>
>+ connector->fence_context = fence_context_alloc(1);
>+ spin_lock_init(&connector->fence_lock);
>+ snprintf(connector->timeline_name, sizeof(connector->timeline_name),
>+ "CONNECTOR:%d", connector->base.id);
>+
>+ drm_object_attach_property(&connector->base,
>+ config->prop_out_fence_ptr, 0);
>+
> drm_object_attach_property(&connector->base,
> config->writeback_fb_id_property, 0);
>
>@@ -155,3 +214,24 @@ fail:
> return ret;
> }
> EXPORT_SYMBOL(drm_writeback_connector_init);
>+
>+struct fence *drm_writeback_get_out_fence(struct drm_connector *connector,
>+ struct drm_connector_state *conn_state)
>+{
>+ struct fence *fence;
>+
>+ if (WARN_ON(connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK))
>+ return NULL;
>+
>+ fence = kzalloc(sizeof(*fence), GFP_KERNEL);
>+ if (!fence)
>+ return NULL;
>+
>+ fence_init(fence, &drm_writeback_fence_ops, &connector->fence_lock,
>+ connector->fence_context, ++connector->fence_seqno);
>+
>+ conn_state->out_fence = fence_get(fence);
>+
>+ return fence;
>+}
>+EXPORT_SYMBOL(drm_writeback_get_out_fence);
>diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
>index a5e3778..7d40537 100644
>--- a/include/drm/drm_connector.h
>+++ b/include/drm/drm_connector.h
>@@ -199,6 +199,7 @@ int drm_display_info_set_bus_formats(struct drm_display_info *info,
> * @best_encoder: can be used by helpers and drivers to select the encoder
> * @state: backpointer to global drm_atomic_state
> * @fb: Writeback framebuffer, for DRM_MODE_CONNECTOR_WRITEBACK
>+ * @out_fence: Fence which will clear when the framebuffer write has finished
> */
> struct drm_connector_state {
> struct drm_connector *connector;
>@@ -216,6 +217,9 @@ struct drm_connector_state {
> struct drm_atomic_state *state;
>
> struct drm_framebuffer *fb; /* do not write directly, use drm_atomic_set_fb_for_connector() */
>+
>+ struct fence *out_fence;
>+ u64 __user *out_fence_ptr;
> };
>
> /**
>@@ -546,6 +550,10 @@ struct drm_cmdline_mode {
> * @tile_v_loc: vertical location of this tile
> * @tile_h_size: horizontal size of this tile.
> * @tile_v_size: vertical size of this tile.
>+ * @fence_context: context for fence signalling
>+ * @fence_lock: fence lock for the fence context
>+ * @fence_seqno: seqno variable to create fences
>+ * @timeline_name: fence timeline name
> *
> * Each connector may be connected to one or more CRTCs, or may be clonable by
> * another connector if they can share a CRTC. Each connector also has a specific
>@@ -694,6 +702,12 @@ struct drm_connector {
> uint8_t num_h_tile, num_v_tile;
> uint8_t tile_h_loc, tile_v_loc;
> uint16_t tile_h_size, tile_v_size;
>+
>+ /* fence timelines info for DRM out-fences */
>+ unsigned int fence_context;
>+ spinlock_t fence_lock;
>+ unsigned long fence_seqno;
>+ char timeline_name[32];
> };
>
> #define obj_to_connector(x) container_of(x, struct drm_connector, base)
>diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
>index afdc2742..01f33bc 100644
>--- a/include/drm/drm_writeback.h
>+++ b/include/drm/drm_writeback.h
>@@ -16,4 +16,6 @@ int drm_writeback_connector_init(struct drm_device *dev,
> const struct drm_connector_funcs *funcs,
> u32 *formats, int n_formats);
>
>+struct fence *drm_writeback_get_out_fence(struct drm_connector *connector,
>+ struct drm_connector_state *conn_state);
> #endif
>--
>1.7.9.5
>
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2016-10-26 Brian Starkey <brian.starkey@arm.com>:
> Add the OUT_FENCE_PTR property to writeback connectors, to enable
> userspace to get a fence which will signal once the writeback is
> complete.
>
> A timeline is added to drm_connector for use by the writeback
> out-fences. It is up to drivers to check for a fence in the
> connector_state and signal the it appropriately when their writeback has
> finished.
>
> It is not allowed to request an out-fence without a framebuffer attached
> to the connector.
>
> Signed-off-by: Brian Starkey <brian.starkey@arm.com>
> ---
> drivers/gpu/drm/drm_atomic.c | 60 +++++++++++++++++++++++---
> drivers/gpu/drm/drm_atomic_helper.c | 5 ++-
> drivers/gpu/drm/drm_writeback.c | 80 +++++++++++++++++++++++++++++++++++
> include/drm/drm_connector.h | 14 ++++++
> include/drm/drm_writeback.h | 2 +
> 5 files changed, 155 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index 3f8fc97..061ea13 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -30,6 +30,7 @@
> #include <drm/drm_atomic.h>
> #include <drm/drm_mode.h>
> #include <drm/drm_plane_helper.h>
> +#include <drm/drm_writeback.h>
> #include <linux/sync_file.h>
>
> #include "drm_crtc_internal.h"
> @@ -646,6 +647,12 @@ static int drm_atomic_connector_check(struct drm_connector *connector,
> return -EINVAL;
> }
>
> + if (state->out_fence && !state->fb) {
> + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] requesting out-fence without framebuffer\n",
> + connector->base.id, connector->name);
> + return -EINVAL;
> + }
> +
> return 0;
> }
>
> @@ -1047,6 +1054,8 @@ int drm_atomic_connector_set_property(struct drm_connector *connector,
> drm_atomic_set_fb_for_connector(state, fb);
> if (fb)
> drm_framebuffer_unreference(fb);
> + } else if (property == config->prop_out_fence_ptr) {
> + state->out_fence_ptr = u64_to_user_ptr(val);
We need to move this out of the conn_state. For my v6 on CRTC out fences
I added drm_atomic_set_out_fence_for_crtc() and
drm_atomic_get_out_fence_for_crtc(). See padovan/fences.
> } else if (connector->funcs->atomic_set_property) {
> return connector->funcs->atomic_set_property(connector,
> state, property, val);
> @@ -1088,6 +1097,8 @@ drm_atomic_connector_get_property(struct drm_connector *connector,
> } else if (property == config->writeback_fb_id_property) {
> /* Writeback framebuffer is one-shot, write and forget */
> *val = 0;
> + } else if (property == config->prop_out_fence_ptr) {
> + *val = 0;
> } else if (connector->funcs->atomic_get_property) {
> return connector->funcs->atomic_get_property(connector,
> state, property, val);
> @@ -1736,6 +1747,39 @@ static int setup_out_fence(struct drm_out_fence_state *fence_state,
> return 0;
> }
>
> +static int setup_connector_out_fences(struct drm_atomic_state *state,
> + struct drm_out_fence_state *fence_state,
> + int *fence_idx)
> +{
> + struct drm_connector *conn;
> + struct drm_connector_state *conn_state;
> + int i, ret;
> +
> + for_each_connector_in_state(state, conn, conn_state, i) {
> + struct fence *fence;
> +
> + if (!conn_state->out_fence_ptr)
> + continue;
> +
> + fence = drm_writeback_get_out_fence(conn, conn_state);
> + if (!fence)
> + return -ENOMEM;
> +
> + ret = setup_out_fence(&fence_state[(*fence_idx)++],
> + conn_state->out_fence_ptr,
> + fence);
> + if (ret) {
> + fence_put(fence);
> + return ret;
> + }
> +
> + /* One-time usage only */
> + conn_state->out_fence_ptr = NULL;
> + }
> +
> + return 0;
> +}
> +
> int drm_mode_atomic_ioctl(struct drm_device *dev,
> void *data, struct drm_file *file_priv)
> {
> @@ -1868,8 +1912,8 @@ retry:
> drm_mode_object_unreference(obj);
> }
>
> - fence_state = kcalloc(dev->mode_config.num_crtc, sizeof(*fence_state),
> - GFP_KERNEL);
> + fence_state = kcalloc(dev->mode_config.num_crtc + state->num_connector,
> + sizeof(*fence_state), GFP_KERNEL);
> if (!fence_state) {
> ret = -ENOMEM;
> goto out;
> @@ -1929,10 +1973,16 @@ retry:
> * Below we call drm_atomic_state_free for it.
> */
> ret = drm_atomic_check_only(state);
> - } else if (arg->flags & DRM_MODE_ATOMIC_NONBLOCK) {
> - ret = drm_atomic_nonblocking_commit(state);
> } else {
> - ret = drm_atomic_commit(state);
> + ret = setup_connector_out_fences(state, fence_state,
> + &fence_idx);
> + if (ret)
> + goto out;
I'd do this before this block. At the DRM_MODE_ATOMIC_TEST_ONLY or we
check or we commit. Moreover you should check if out_fences
are not set with TEST_ONLY.
> +
> + if (arg->flags & DRM_MODE_ATOMIC_NONBLOCK)
> + ret = drm_atomic_nonblocking_commit(state);
> + else
> + ret = drm_atomic_commit(state);
> }
>
> if (!ret)
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index bba8672..88da299 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -3234,8 +3234,9 @@ __drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector,
> if (state->crtc)
> drm_connector_reference(connector);
>
> - /* Don't copy over framebuffers, they are used only once */
> + /* Don't copy over framebuffers or fences, they are used only once */
> state->fb = NULL;
> + state->out_fence = NULL;
> }
> EXPORT_SYMBOL(__drm_atomic_helper_connector_duplicate_state);
>
> @@ -3365,6 +3366,8 @@ __drm_atomic_helper_connector_destroy_state(struct drm_connector_state *state)
> drm_connector_unreference(state->connector);
> if (state->fb)
> drm_framebuffer_unreference(state->fb);
> +
> + fence_put(state->out_fence);
> }
> EXPORT_SYMBOL(__drm_atomic_helper_connector_destroy_state);
>
> diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
> index 5a6e0ad..4a6ef30 100644
> --- a/drivers/gpu/drm/drm_writeback.c
> +++ b/drivers/gpu/drm/drm_writeback.c
> @@ -11,6 +11,7 @@
> #include <drm/drm_crtc.h>
> #include <drm/drm_property.h>
> #include <drm/drmP.h>
> +#include <linux/fence.h>
>
> /**
> * DOC: overview
> @@ -32,6 +33,16 @@
> * explicitly cleared in order to make a subsequent commit which doesn't use
> * writeback.
> *
> + * Unlike with planes, when a writeback framebuffer is removed by userspace DRM
> + * makes no attempt to remove it from active use by the connector. This is
> + * because no method is provided to abort a writeback operation, and in any
> + * case making a new commit whilst a writeback is ongoing is undefined (see
> + * OUT_FENCE_PTR below). As soon as the current writeback is finished, the
> + * framebuffer will automatically no longer be in active use. As it will also
> + * have already been removed from the framebuffer list, there will be no way for
> + * any userspace application to retrieve a reference to it in the intervening
> + * period.
> + *
> * Writeback connectors have several additional properties, which userspace
> * can use to query and control them:
> *
> @@ -52,8 +63,48 @@
> * "PIXEL_FORMATS_SIZE":
> * Immutable unsigned range property storing the number of entries in the
> * PIXEL_FORMATS array.
> + *
> + * "OUT_FENCE_PTR":
> + * Userspace can provide the address of a 64-bit integer in this property,
> + * which will be filled with a sync_file file descriptor by the kernel.
> + * The sync_file will signal when the associated writeback has finished.
> + * Userspace should wait for this fence to signal before making another
> + * commit affecting any of the same CRTCs, Planes or Connectors.
> + * **Failure to do so will result in undefined behaviour.**
> + * For this reason it is strongly recommended that all userspace
> + * applications making use of writeback connectors *always* retrieve an
> + * out-fence for the commit and use it appropriately.
> + * From userspace, this property will always read as zero.
> */
>
> +#define fence_to_connector(x) container_of(x->lock, struct drm_connector, fence_lock)
> +
> +static const char *drm_writeback_fence_get_driver_name(struct fence *fence)
> +{
> + struct drm_connector *connector = fence_to_connector(fence);
> +
> + return connector->dev->driver->name;
> +}
> +
> +static const char *drm_writeback_fence_get_timeline_name(struct fence *fence)
> +{
> + struct drm_connector *connector = fence_to_connector(fence);
> +
> + return connector->timeline_name;
> +}
> +
> +static bool drm_writeback_fence_enable_signaling(struct fence *fence)
> +{
> + return true;
> +}
> +
> +static const struct fence_ops drm_writeback_fence_ops = {
> + .get_driver_name = drm_writeback_fence_get_driver_name,
> + .get_timeline_name = drm_writeback_fence_get_timeline_name,
> + .enable_signaling = drm_writeback_fence_enable_signaling,
> + .wait = fence_default_wait,
> +};
> +
> /**
> * create_writeback_properties - Create writeback connector-specific properties
> * @dev: DRM device
> @@ -136,6 +187,14 @@ int drm_writeback_connector_init(struct drm_device *dev,
> if (ret)
> goto fail;
>
> + connector->fence_context = fence_context_alloc(1);
> + spin_lock_init(&connector->fence_lock);
> + snprintf(connector->timeline_name, sizeof(connector->timeline_name),
> + "CONNECTOR:%d", connector->base.id);
> +
> + drm_object_attach_property(&connector->base,
> + config->prop_out_fence_ptr, 0);
> +
> drm_object_attach_property(&connector->base,
> config->writeback_fb_id_property, 0);
>
> @@ -155,3 +214,24 @@ fail:
> return ret;
> }
> EXPORT_SYMBOL(drm_writeback_connector_init);
> +
> +struct fence *drm_writeback_get_out_fence(struct drm_connector *connector,
> + struct drm_connector_state *conn_state)
> +{
> + struct fence *fence;
> +
> + if (WARN_ON(connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK))
> + return NULL;
> +
> + fence = kzalloc(sizeof(*fence), GFP_KERNEL);
> + if (!fence)
> + return NULL;
> +
> + fence_init(fence, &drm_writeback_fence_ops, &connector->fence_lock,
> + connector->fence_context, ++connector->fence_seqno);
> +
> + conn_state->out_fence = fence_get(fence);
> +
> + return fence;
> +}
> +EXPORT_SYMBOL(drm_writeback_get_out_fence);
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index a5e3778..7d40537 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -199,6 +199,7 @@ int drm_display_info_set_bus_formats(struct drm_display_info *info,
> * @best_encoder: can be used by helpers and drivers to select the encoder
> * @state: backpointer to global drm_atomic_state
> * @fb: Writeback framebuffer, for DRM_MODE_CONNECTOR_WRITEBACK
> + * @out_fence: Fence which will clear when the framebuffer write has finished
> */
> struct drm_connector_state {
> struct drm_connector *connector;
> @@ -216,6 +217,9 @@ struct drm_connector_state {
> struct drm_atomic_state *state;
>
> struct drm_framebuffer *fb; /* do not write directly, use drm_atomic_set_fb_for_connector() */
> +
> + struct fence *out_fence;
> + u64 __user *out_fence_ptr;
> };
>
> /**
> @@ -546,6 +550,10 @@ struct drm_cmdline_mode {
> * @tile_v_loc: vertical location of this tile
> * @tile_h_size: horizontal size of this tile.
> * @tile_v_size: vertical size of this tile.
> + * @fence_context: context for fence signalling
> + * @fence_lock: fence lock for the fence context
> + * @fence_seqno: seqno variable to create fences
> + * @timeline_name: fence timeline name
> *
> * Each connector may be connected to one or more CRTCs, or may be clonable by
> * another connector if they can share a CRTC. Each connector also has a specific
> @@ -694,6 +702,12 @@ struct drm_connector {
> uint8_t num_h_tile, num_v_tile;
> uint8_t tile_h_loc, tile_v_loc;
> uint16_t tile_h_size, tile_v_size;
> +
> + /* fence timelines info for DRM out-fences */
> + unsigned int fence_context;
> + spinlock_t fence_lock;
> + unsigned long fence_seqno;
> + char timeline_name[32];
> };
>
> #define obj_to_connector(x) container_of(x, struct drm_connector, base)
> diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
> index afdc2742..01f33bc 100644
> --- a/include/drm/drm_writeback.h
> +++ b/include/drm/drm_writeback.h
> @@ -16,4 +16,6 @@ int drm_writeback_connector_init(struct drm_device *dev,
> const struct drm_connector_funcs *funcs,
> u32 *formats, int n_formats);
>
> +struct fence *drm_writeback_get_out_fence(struct drm_connector *connector,
> + struct drm_connector_state *conn_state);
> #endif
> --
> 1.7.9.5
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
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Hi Gustavo,
On Wed, Oct 26, 2016 at 07:40:29PM -0200, Gustavo Padovan wrote:
>2016-10-26 Brian Starkey <brian.starkey@arm.com>:
>
>> Add the OUT_FENCE_PTR property to writeback connectors, to enable
>> userspace to get a fence which will signal once the writeback is
>> complete.
>>
>> A timeline is added to drm_connector for use by the writeback
>> out-fences. It is up to drivers to check for a fence in the
>> connector_state and signal the it appropriately when their writeback has
>> finished.
>>
>> It is not allowed to request an out-fence without a framebuffer attached
>> to the connector.
>>
>> Signed-off-by: Brian Starkey <brian.starkey@arm.com>
>> ---
>> drivers/gpu/drm/drm_atomic.c | 60 +++++++++++++++++++++++---
>> drivers/gpu/drm/drm_atomic_helper.c | 5 ++-
>> drivers/gpu/drm/drm_writeback.c | 80 +++++++++++++++++++++++++++++++++++
>> include/drm/drm_connector.h | 14 ++++++
>> include/drm/drm_writeback.h | 2 +
>> 5 files changed, 155 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
>> index 3f8fc97..061ea13 100644
>> --- a/drivers/gpu/drm/drm_atomic.c
>> +++ b/drivers/gpu/drm/drm_atomic.c
>> @@ -30,6 +30,7 @@
>> #include <drm/drm_atomic.h>
>> #include <drm/drm_mode.h>
>> #include <drm/drm_plane_helper.h>
>> +#include <drm/drm_writeback.h>
>> #include <linux/sync_file.h>
>>
>> #include "drm_crtc_internal.h"
>> @@ -646,6 +647,12 @@ static int drm_atomic_connector_check(struct drm_connector *connector,
>> return -EINVAL;
>> }
>>
>> + if (state->out_fence && !state->fb) {
>> + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] requesting out-fence without framebuffer\n",
>> + connector->base.id, connector->name);
>> + return -EINVAL;
>> + }
>> +
>> return 0;
>> }
>>
>> @@ -1047,6 +1054,8 @@ int drm_atomic_connector_set_property(struct drm_connector *connector,
>> drm_atomic_set_fb_for_connector(state, fb);
>> if (fb)
>> drm_framebuffer_unreference(fb);
>> + } else if (property == config->prop_out_fence_ptr) {
>> + state->out_fence_ptr = u64_to_user_ptr(val);
>
>We need to move this out of the conn_state. For my v6 on CRTC out fences
>I added drm_atomic_set_out_fence_for_crtc() and
>drm_atomic_get_out_fence_for_crtc(). See padovan/fences.
>
Yep, will do. I was expecting this to change
>> } else if (connector->funcs->atomic_set_property) {
>> return connector->funcs->atomic_set_property(connector,
>> state, property, val);
>> @@ -1088,6 +1097,8 @@ drm_atomic_connector_get_property(struct drm_connector *connector,
>> } else if (property == config->writeback_fb_id_property) {
>> /* Writeback framebuffer is one-shot, write and forget */
>> *val = 0;
>> + } else if (property == config->prop_out_fence_ptr) {
>> + *val = 0;
>> } else if (connector->funcs->atomic_get_property) {
>> return connector->funcs->atomic_get_property(connector,
>> state, property, val);
>> @@ -1736,6 +1747,39 @@ static int setup_out_fence(struct drm_out_fence_state *fence_state,
>> return 0;
>> }
>>
>> +static int setup_connector_out_fences(struct drm_atomic_state *state,
>> + struct drm_out_fence_state *fence_state,
>> + int *fence_idx)
>> +{
>> + struct drm_connector *conn;
>> + struct drm_connector_state *conn_state;
>> + int i, ret;
>> +
>> + for_each_connector_in_state(state, conn, conn_state, i) {
>> + struct fence *fence;
>> +
>> + if (!conn_state->out_fence_ptr)
>> + continue;
>> +
>> + fence = drm_writeback_get_out_fence(conn, conn_state);
>> + if (!fence)
>> + return -ENOMEM;
>> +
>> + ret = setup_out_fence(&fence_state[(*fence_idx)++],
>> + conn_state->out_fence_ptr,
>> + fence);
>> + if (ret) {
>> + fence_put(fence);
>> + return ret;
>> + }
>> +
>> + /* One-time usage only */
>> + conn_state->out_fence_ptr = NULL;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> int drm_mode_atomic_ioctl(struct drm_device *dev,
>> void *data, struct drm_file *file_priv)
>> {
>> @@ -1868,8 +1912,8 @@ retry:
>> drm_mode_object_unreference(obj);
>> }
>>
>> - fence_state = kcalloc(dev->mode_config.num_crtc, sizeof(*fence_state),
>> - GFP_KERNEL);
>> + fence_state = kcalloc(dev->mode_config.num_crtc + state->num_connector,
>> + sizeof(*fence_state), GFP_KERNEL);
>> if (!fence_state) {
>> ret = -ENOMEM;
>> goto out;
>> @@ -1929,10 +1973,16 @@ retry:
>> * Below we call drm_atomic_state_free for it.
>> */
>> ret = drm_atomic_check_only(state);
>> - } else if (arg->flags & DRM_MODE_ATOMIC_NONBLOCK) {
>> - ret = drm_atomic_nonblocking_commit(state);
>> } else {
>> - ret = drm_atomic_commit(state);
>> + ret = setup_connector_out_fences(state, fence_state,
>> + &fence_idx);
>> + if (ret)
>> + goto out;
>
>I'd do this before this block. At the DRM_MODE_ATOMIC_TEST_ONLY or we
>check or we commit. Moreover you should check if out_fences
>are not set with TEST_ONLY.
>
I don't quite follow the second sentence; you mean you'd rather I
was finished setting things up before the TEST_ONLY check? That sounds
OK.
For TEST_ONLY I actually think we shouldn't reject commits with
OUT_FENCE_PTRs and TEST_ONLY. I thought the idea of TEST_ONLY was for
userspace to build a commit, then see if it can work, then commit it
for real.
By rejecting TEST_ONLY + OUT_FENCE_PTRs you're saying userspace can
never test what it actually intends to commit. It has to test, then
add the out-fences, then commit and hope for the best.
How about always setting the out-fences to -1 for TEST_ONLY?
Thanks for the review,
-Brian
>> +
>> + if (arg->flags & DRM_MODE_ATOMIC_NONBLOCK)
>> + ret = drm_atomic_nonblocking_commit(state);
>> + else
>> + ret = drm_atomic_commit(state);
>> }
>>
>> if (!ret)
>> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
>> index bba8672..88da299 100644
>> --- a/drivers/gpu/drm/drm_atomic_helper.c
>> +++ b/drivers/gpu/drm/drm_atomic_helper.c
>> @@ -3234,8 +3234,9 @@ __drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector,
>> if (state->crtc)
>> drm_connector_reference(connector);
>>
>> - /* Don't copy over framebuffers, they are used only once */
>> + /* Don't copy over framebuffers or fences, they are used only once */
>> state->fb = NULL;
>> + state->out_fence = NULL;
>> }
>> EXPORT_SYMBOL(__drm_atomic_helper_connector_duplicate_state);
>>
>> @@ -3365,6 +3366,8 @@ __drm_atomic_helper_connector_destroy_state(struct drm_connector_state *state)
>> drm_connector_unreference(state->connector);
>> if (state->fb)
>> drm_framebuffer_unreference(state->fb);
>> +
>> + fence_put(state->out_fence);
>> }
>> EXPORT_SYMBOL(__drm_atomic_helper_connector_destroy_state);
>>
>> diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
>> index 5a6e0ad..4a6ef30 100644
>> --- a/drivers/gpu/drm/drm_writeback.c
>> +++ b/drivers/gpu/drm/drm_writeback.c
>> @@ -11,6 +11,7 @@
>> #include <drm/drm_crtc.h>
>> #include <drm/drm_property.h>
>> #include <drm/drmP.h>
>> +#include <linux/fence.h>
>>
>> /**
>> * DOC: overview
>> @@ -32,6 +33,16 @@
>> * explicitly cleared in order to make a subsequent commit which doesn't use
>> * writeback.
>> *
>> + * Unlike with planes, when a writeback framebuffer is removed by userspace DRM
>> + * makes no attempt to remove it from active use by the connector. This is
>> + * because no method is provided to abort a writeback operation, and in any
>> + * case making a new commit whilst a writeback is ongoing is undefined (see
>> + * OUT_FENCE_PTR below). As soon as the current writeback is finished, the
>> + * framebuffer will automatically no longer be in active use. As it will also
>> + * have already been removed from the framebuffer list, there will be no way for
>> + * any userspace application to retrieve a reference to it in the intervening
>> + * period.
>> + *
>> * Writeback connectors have several additional properties, which userspace
>> * can use to query and control them:
>> *
>> @@ -52,8 +63,48 @@
>> * "PIXEL_FORMATS_SIZE":
>> * Immutable unsigned range property storing the number of entries in the
>> * PIXEL_FORMATS array.
>> + *
>> + * "OUT_FENCE_PTR":
>> + * Userspace can provide the address of a 64-bit integer in this property,
>> + * which will be filled with a sync_file file descriptor by the kernel.
>> + * The sync_file will signal when the associated writeback has finished.
>> + * Userspace should wait for this fence to signal before making another
>> + * commit affecting any of the same CRTCs, Planes or Connectors.
>> + * **Failure to do so will result in undefined behaviour.**
>> + * For this reason it is strongly recommended that all userspace
>> + * applications making use of writeback connectors *always* retrieve an
>> + * out-fence for the commit and use it appropriately.
>> + * From userspace, this property will always read as zero.
>> */
>>
>> +#define fence_to_connector(x) container_of(x->lock, struct drm_connector, fence_lock)
>> +
>> +static const char *drm_writeback_fence_get_driver_name(struct fence *fence)
>> +{
>> + struct drm_connector *connector = fence_to_connector(fence);
>> +
>> + return connector->dev->driver->name;
>> +}
>> +
>> +static const char *drm_writeback_fence_get_timeline_name(struct fence *fence)
>> +{
>> + struct drm_connector *connector = fence_to_connector(fence);
>> +
>> + return connector->timeline_name;
>> +}
>> +
>> +static bool drm_writeback_fence_enable_signaling(struct fence *fence)
>> +{
>> + return true;
>> +}
>> +
>> +static const struct fence_ops drm_writeback_fence_ops = {
>> + .get_driver_name = drm_writeback_fence_get_driver_name,
>> + .get_timeline_name = drm_writeback_fence_get_timeline_name,
>> + .enable_signaling = drm_writeback_fence_enable_signaling,
>> + .wait = fence_default_wait,
>> +};
>> +
>> /**
>> * create_writeback_properties - Create writeback connector-specific properties
>> * @dev: DRM device
>> @@ -136,6 +187,14 @@ int drm_writeback_connector_init(struct drm_device *dev,
>> if (ret)
>> goto fail;
>>
>> + connector->fence_context = fence_context_alloc(1);
>> + spin_lock_init(&connector->fence_lock);
>> + snprintf(connector->timeline_name, sizeof(connector->timeline_name),
>> + "CONNECTOR:%d", connector->base.id);
>> +
>> + drm_object_attach_property(&connector->base,
>> + config->prop_out_fence_ptr, 0);
>> +
>> drm_object_attach_property(&connector->base,
>> config->writeback_fb_id_property, 0);
>>
>> @@ -155,3 +214,24 @@ fail:
>> return ret;
>> }
>> EXPORT_SYMBOL(drm_writeback_connector_init);
>> +
>> +struct fence *drm_writeback_get_out_fence(struct drm_connector *connector,
>> + struct drm_connector_state *conn_state)
>> +{
>> + struct fence *fence;
>> +
>> + if (WARN_ON(connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK))
>> + return NULL;
>> +
>> + fence = kzalloc(sizeof(*fence), GFP_KERNEL);
>> + if (!fence)
>> + return NULL;
>> +
>> + fence_init(fence, &drm_writeback_fence_ops, &connector->fence_lock,
>> + connector->fence_context, ++connector->fence_seqno);
>> +
>> + conn_state->out_fence = fence_get(fence);
>> +
>> + return fence;
>> +}
>> +EXPORT_SYMBOL(drm_writeback_get_out_fence);
>> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
>> index a5e3778..7d40537 100644
>> --- a/include/drm/drm_connector.h
>> +++ b/include/drm/drm_connector.h
>> @@ -199,6 +199,7 @@ int drm_display_info_set_bus_formats(struct drm_display_info *info,
>> * @best_encoder: can be used by helpers and drivers to select the encoder
>> * @state: backpointer to global drm_atomic_state
>> * @fb: Writeback framebuffer, for DRM_MODE_CONNECTOR_WRITEBACK
>> + * @out_fence: Fence which will clear when the framebuffer write has finished
>> */
>> struct drm_connector_state {
>> struct drm_connector *connector;
>> @@ -216,6 +217,9 @@ struct drm_connector_state {
>> struct drm_atomic_state *state;
>>
>> struct drm_framebuffer *fb; /* do not write directly, use drm_atomic_set_fb_for_connector() */
>> +
>> + struct fence *out_fence;
>> + u64 __user *out_fence_ptr;
>> };
>>
>> /**
>> @@ -546,6 +550,10 @@ struct drm_cmdline_mode {
>> * @tile_v_loc: vertical location of this tile
>> * @tile_h_size: horizontal size of this tile.
>> * @tile_v_size: vertical size of this tile.
>> + * @fence_context: context for fence signalling
>> + * @fence_lock: fence lock for the fence context
>> + * @fence_seqno: seqno variable to create fences
>> + * @timeline_name: fence timeline name
>> *
>> * Each connector may be connected to one or more CRTCs, or may be clonable by
>> * another connector if they can share a CRTC. Each connector also has a specific
>> @@ -694,6 +702,12 @@ struct drm_connector {
>> uint8_t num_h_tile, num_v_tile;
>> uint8_t tile_h_loc, tile_v_loc;
>> uint16_t tile_h_size, tile_v_size;
>> +
>> + /* fence timelines info for DRM out-fences */
>> + unsigned int fence_context;
>> + spinlock_t fence_lock;
>> + unsigned long fence_seqno;
>> + char timeline_name[32];
>> };
>>
>> #define obj_to_connector(x) container_of(x, struct drm_connector, base)
>> diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
>> index afdc2742..01f33bc 100644
>> --- a/include/drm/drm_writeback.h
>> +++ b/include/drm/drm_writeback.h
>> @@ -16,4 +16,6 @@ int drm_writeback_connector_init(struct drm_device *dev,
>> const struct drm_connector_funcs *funcs,
>> u32 *formats, int n_formats);
>>
>> +struct fence *drm_writeback_get_out_fence(struct drm_connector *connector,
>> + struct drm_connector_state *conn_state);
>> #endif
>> --
>> 1.7.9.5
>>
>> _______________________________________________
>> dri-devel mailing list
>> dri-devel@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
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@@ -30,6 +30,7 @@
#include <drm/drm_atomic.h>
#include <drm/drm_mode.h>
#include <drm/drm_plane_helper.h>
+#include <drm/drm_writeback.h>
#include <linux/sync_file.h>
#include "drm_crtc_internal.h"
@@ -646,6 +647,12 @@ static int drm_atomic_connector_check(struct drm_connector *connector,
return -EINVAL;
}
+ if (state->out_fence && !state->fb) {
+ DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] requesting out-fence without framebuffer\n",
+ connector->base.id, connector->name);
+ return -EINVAL;
+ }
+
return 0;
}
@@ -1047,6 +1054,8 @@ int drm_atomic_connector_set_property(struct drm_connector *connector,
drm_atomic_set_fb_for_connector(state, fb);
if (fb)
drm_framebuffer_unreference(fb);
+ } else if (property == config->prop_out_fence_ptr) {
+ state->out_fence_ptr = u64_to_user_ptr(val);
} else if (connector->funcs->atomic_set_property) {
return connector->funcs->atomic_set_property(connector,
state, property, val);
@@ -1088,6 +1097,8 @@ drm_atomic_connector_get_property(struct drm_connector *connector,
} else if (property == config->writeback_fb_id_property) {
/* Writeback framebuffer is one-shot, write and forget */
*val = 0;
+ } else if (property == config->prop_out_fence_ptr) {
+ *val = 0;
} else if (connector->funcs->atomic_get_property) {
return connector->funcs->atomic_get_property(connector,
state, property, val);
@@ -1736,6 +1747,39 @@ static int setup_out_fence(struct drm_out_fence_state *fence_state,
return 0;
}
+static int setup_connector_out_fences(struct drm_atomic_state *state,
+ struct drm_out_fence_state *fence_state,
+ int *fence_idx)
+{
+ struct drm_connector *conn;
+ struct drm_connector_state *conn_state;
+ int i, ret;
+
+ for_each_connector_in_state(state, conn, conn_state, i) {
+ struct fence *fence;
+
+ if (!conn_state->out_fence_ptr)
+ continue;
+
+ fence = drm_writeback_get_out_fence(conn, conn_state);
+ if (!fence)
+ return -ENOMEM;
+
+ ret = setup_out_fence(&fence_state[(*fence_idx)++],
+ conn_state->out_fence_ptr,
+ fence);
+ if (ret) {
+ fence_put(fence);
+ return ret;
+ }
+
+ /* One-time usage only */
+ conn_state->out_fence_ptr = NULL;
+ }
+
+ return 0;
+}
+
int drm_mode_atomic_ioctl(struct drm_device *dev,
void *data, struct drm_file *file_priv)
{
@@ -1868,8 +1912,8 @@ retry:
drm_mode_object_unreference(obj);
}
- fence_state = kcalloc(dev->mode_config.num_crtc, sizeof(*fence_state),
- GFP_KERNEL);
+ fence_state = kcalloc(dev->mode_config.num_crtc + state->num_connector,
+ sizeof(*fence_state), GFP_KERNEL);
if (!fence_state) {
ret = -ENOMEM;
goto out;
@@ -1929,10 +1973,16 @@ retry:
* Below we call drm_atomic_state_free for it.
*/
ret = drm_atomic_check_only(state);
- } else if (arg->flags & DRM_MODE_ATOMIC_NONBLOCK) {
- ret = drm_atomic_nonblocking_commit(state);
} else {
- ret = drm_atomic_commit(state);
+ ret = setup_connector_out_fences(state, fence_state,
+ &fence_idx);
+ if (ret)
+ goto out;
+
+ if (arg->flags & DRM_MODE_ATOMIC_NONBLOCK)
+ ret = drm_atomic_nonblocking_commit(state);
+ else
+ ret = drm_atomic_commit(state);
}
if (!ret)
@@ -3234,8 +3234,9 @@ __drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector,
if (state->crtc)
drm_connector_reference(connector);
- /* Don't copy over framebuffers, they are used only once */
+ /* Don't copy over framebuffers or fences, they are used only once */
state->fb = NULL;
+ state->out_fence = NULL;
}
EXPORT_SYMBOL(__drm_atomic_helper_connector_duplicate_state);
@@ -3365,6 +3366,8 @@ __drm_atomic_helper_connector_destroy_state(struct drm_connector_state *state)
drm_connector_unreference(state->connector);
if (state->fb)
drm_framebuffer_unreference(state->fb);
+
+ fence_put(state->out_fence);
}
EXPORT_SYMBOL(__drm_atomic_helper_connector_destroy_state);
@@ -11,6 +11,7 @@
#include <drm/drm_crtc.h>
#include <drm/drm_property.h>
#include <drm/drmP.h>
+#include <linux/fence.h>
/**
* DOC: overview
@@ -32,6 +33,16 @@
* explicitly cleared in order to make a subsequent commit which doesn't use
* writeback.
*
+ * Unlike with planes, when a writeback framebuffer is removed by userspace DRM
+ * makes no attempt to remove it from active use by the connector. This is
+ * because no method is provided to abort a writeback operation, and in any
+ * case making a new commit whilst a writeback is ongoing is undefined (see
+ * OUT_FENCE_PTR below). As soon as the current writeback is finished, the
+ * framebuffer will automatically no longer be in active use. As it will also
+ * have already been removed from the framebuffer list, there will be no way for
+ * any userspace application to retrieve a reference to it in the intervening
+ * period.
+ *
* Writeback connectors have several additional properties, which userspace
* can use to query and control them:
*
@@ -52,8 +63,48 @@
* "PIXEL_FORMATS_SIZE":
* Immutable unsigned range property storing the number of entries in the
* PIXEL_FORMATS array.
+ *
+ * "OUT_FENCE_PTR":
+ * Userspace can provide the address of a 64-bit integer in this property,
+ * which will be filled with a sync_file file descriptor by the kernel.
+ * The sync_file will signal when the associated writeback has finished.
+ * Userspace should wait for this fence to signal before making another
+ * commit affecting any of the same CRTCs, Planes or Connectors.
+ * **Failure to do so will result in undefined behaviour.**
+ * For this reason it is strongly recommended that all userspace
+ * applications making use of writeback connectors *always* retrieve an
+ * out-fence for the commit and use it appropriately.
+ * From userspace, this property will always read as zero.
*/
+#define fence_to_connector(x) container_of(x->lock, struct drm_connector, fence_lock)
+
+static const char *drm_writeback_fence_get_driver_name(struct fence *fence)
+{
+ struct drm_connector *connector = fence_to_connector(fence);
+
+ return connector->dev->driver->name;
+}
+
+static const char *drm_writeback_fence_get_timeline_name(struct fence *fence)
+{
+ struct drm_connector *connector = fence_to_connector(fence);
+
+ return connector->timeline_name;
+}
+
+static bool drm_writeback_fence_enable_signaling(struct fence *fence)
+{
+ return true;
+}
+
+static const struct fence_ops drm_writeback_fence_ops = {
+ .get_driver_name = drm_writeback_fence_get_driver_name,
+ .get_timeline_name = drm_writeback_fence_get_timeline_name,
+ .enable_signaling = drm_writeback_fence_enable_signaling,
+ .wait = fence_default_wait,
+};
+
/**
* create_writeback_properties - Create writeback connector-specific properties
* @dev: DRM device
@@ -136,6 +187,14 @@ int drm_writeback_connector_init(struct drm_device *dev,
if (ret)
goto fail;
+ connector->fence_context = fence_context_alloc(1);
+ spin_lock_init(&connector->fence_lock);
+ snprintf(connector->timeline_name, sizeof(connector->timeline_name),
+ "CONNECTOR:%d", connector->base.id);
+
+ drm_object_attach_property(&connector->base,
+ config->prop_out_fence_ptr, 0);
+
drm_object_attach_property(&connector->base,
config->writeback_fb_id_property, 0);
@@ -155,3 +214,24 @@ fail:
return ret;
}
EXPORT_SYMBOL(drm_writeback_connector_init);
+
+struct fence *drm_writeback_get_out_fence(struct drm_connector *connector,
+ struct drm_connector_state *conn_state)
+{
+ struct fence *fence;
+
+ if (WARN_ON(connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK))
+ return NULL;
+
+ fence = kzalloc(sizeof(*fence), GFP_KERNEL);
+ if (!fence)
+ return NULL;
+
+ fence_init(fence, &drm_writeback_fence_ops, &connector->fence_lock,
+ connector->fence_context, ++connector->fence_seqno);
+
+ conn_state->out_fence = fence_get(fence);
+
+ return fence;
+}
+EXPORT_SYMBOL(drm_writeback_get_out_fence);
@@ -199,6 +199,7 @@ int drm_display_info_set_bus_formats(struct drm_display_info *info,
* @best_encoder: can be used by helpers and drivers to select the encoder
* @state: backpointer to global drm_atomic_state
* @fb: Writeback framebuffer, for DRM_MODE_CONNECTOR_WRITEBACK
+ * @out_fence: Fence which will clear when the framebuffer write has finished
*/
struct drm_connector_state {
struct drm_connector *connector;
@@ -216,6 +217,9 @@ struct drm_connector_state {
struct drm_atomic_state *state;
struct drm_framebuffer *fb; /* do not write directly, use drm_atomic_set_fb_for_connector() */
+
+ struct fence *out_fence;
+ u64 __user *out_fence_ptr;
};
/**
@@ -546,6 +550,10 @@ struct drm_cmdline_mode {
* @tile_v_loc: vertical location of this tile
* @tile_h_size: horizontal size of this tile.
* @tile_v_size: vertical size of this tile.
+ * @fence_context: context for fence signalling
+ * @fence_lock: fence lock for the fence context
+ * @fence_seqno: seqno variable to create fences
+ * @timeline_name: fence timeline name
*
* Each connector may be connected to one or more CRTCs, or may be clonable by
* another connector if they can share a CRTC. Each connector also has a specific
@@ -694,6 +702,12 @@ struct drm_connector {
uint8_t num_h_tile, num_v_tile;
uint8_t tile_h_loc, tile_v_loc;
uint16_t tile_h_size, tile_v_size;
+
+ /* fence timelines info for DRM out-fences */
+ unsigned int fence_context;
+ spinlock_t fence_lock;
+ unsigned long fence_seqno;
+ char timeline_name[32];
};
#define obj_to_connector(x) container_of(x, struct drm_connector, base)
@@ -16,4 +16,6 @@ int drm_writeback_connector_init(struct drm_device *dev,
const struct drm_connector_funcs *funcs,
u32 *formats, int n_formats);
+struct fence *drm_writeback_get_out_fence(struct drm_connector *connector,
+ struct drm_connector_state *conn_state);
#endif