LinuxTV Patchwork [RFCv2] videodev2.h: introduce VIDIOC_DQ_EXT_EVENT

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Submitter Hans Verkuil
Date Feb. 5, 2019, 1:49 p.m.
Message ID <a28bda76-c8e5-7e93-43a0-0d07844cebf0@xs4all.nl>
Download mbox | patch
Permalink /patch/54304/
State New
Delegated to: Hans Verkuil
Headers show

Comments

Hans Verkuil - Feb. 5, 2019, 1:49 p.m.
This patch adds an extended version of VIDIOC_DQEVENT that:

1) is Y2038 safe by using a __u64 for the timestamp
2) needs no compat32 conversion code
3) is able to handle control events from 64-bit control types
   by changing the type of the minimum, maximum, step and default_value
   field to __u64

All drivers and frameworks will be using this, and v4l2-ioctl.c would be the
only place where the old event ioctl and structs are used.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
I chose to name this DQ_EXT_EVENT since the struct it dequeues is now called
v4l2_ext_event. This is also consistent with the names of the G/S/TRY_EXT_CTRLS
ioctls. An alternative could be VIDIOC_DQEXT_EVENT as that would be consistent
with the lack of _ between DQ and EVENT in the current ioctl. But somehow it
doesn't look right.

Changes since v1:
- rename ioctl from VIDIOC_DQEXTEVENT.
- move the reserved array up to right after the union: this will allow us to
  extend the union into the reserved array if we ever need more than 64 bytes
  for the event payload (suggested by Sakari).
---

Patch

diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 9a920f071ff9..301e3678bdb0 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -2303,6 +2303,37 @@  struct v4l2_event {
 	__u32				reserved[8];
 };

+struct v4l2_event_ext_ctrl {
+	__u32 changes;
+	__u32 type;
+	union {
+		__s32 value;
+		__s64 value64;
+	};
+	__s64 minimum;
+	__s64 maximum;
+	__s64 step;
+	__s64 default_value;
+	__u32 flags;
+};
+
+struct v4l2_ext_event {
+	__u32				type;
+	__u32				id;
+	union {
+		struct v4l2_event_vsync		vsync;
+		struct v4l2_event_ext_ctrl	ctrl;
+		struct v4l2_event_frame_sync	frame_sync;
+		struct v4l2_event_src_change	src_change;
+		struct v4l2_event_motion_det	motion_det;
+		__u8				data[64];
+	} u;
+	__u32				reserved[8];
+	__u64				timestamp;
+	__u32				pending;
+	__u32				sequence;
+};
+
 #define V4L2_EVENT_SUB_FL_SEND_INITIAL		(1 << 0)
 #define V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK	(1 << 1)

@@ -2475,6 +2506,7 @@  struct v4l2_create_buffers {
 #define VIDIOC_DBG_G_CHIP_INFO  _IOWR('V', 102, struct v4l2_dbg_chip_info)

 #define VIDIOC_QUERY_EXT_CTRL	_IOWR('V', 103, struct v4l2_query_ext_ctrl)
+#define	VIDIOC_DQ_EXT_EVENT	 _IOR('V', 104, struct v4l2_ext_event)

 /* Reminder: when adding new ioctls please add support for them to
    drivers/media/v4l2-core/v4l2-compat-ioctl32.c as well! */

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