From patchwork Sat Jun 2 15:04:17 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Klaus Schmidinger X-Patchwork-Id: 11574 Received: from mail.tu-berlin.de ([130.149.7.33]) by www.linuxtv.org with esmtp (Exim 4.72) (envelope-from ) id 1Sapzt-0005gw-TJ for patchwork@linuxtv.org; Sat, 02 Jun 2012 17:12:09 +0200 X-tubIT-Incoming-IP: 209.132.180.67 Received: from vger.kernel.org ([209.132.180.67]) by mail.tu-berlin.de (exim-4.75/mailfrontend-4) with esmtp for id 1Sapzs-00054P-Ci; Sat, 02 Jun 2012 17:12:09 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757990Ab2FBPLc (ORCPT ); Sat, 2 Jun 2012 11:11:32 -0400 Received: from racoon.tvdr.de ([188.40.50.18]:33906 "EHLO racoon.tvdr.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757909Ab2FBPLc (ORCPT ); Sat, 2 Jun 2012 11:11:32 -0400 X-Greylist: delayed 426 seconds by postgrey-1.27 at vger.kernel.org; Sat, 02 Jun 2012 11:11:31 EDT Received: from dolphin.tvdr.de (dolphin.tvdr.de [192.168.100.2]) by racoon.tvdr.de (8.14.3/8.14.3) with ESMTP id q52F55XT024654 for ; Sat, 2 Jun 2012 17:05:05 +0200 Received: from [192.168.100.10] (hawk.tvdr.de [192.168.100.10]) by dolphin.tvdr.de (8.14.4/8.14.4) with ESMTP id q52F4Hbv031354 for ; Sat, 2 Jun 2012 17:04:18 +0200 Message-ID: <4FCA2B71.7060700@tvdr.de> Date: Sat, 02 Jun 2012 17:04:17 +0200 From: Klaus Schmidinger User-Agent: Mozilla/5.0 (X11; Linux i686; rv:12.0) Gecko/20120421 Thunderbird/12.0 MIME-Version: 1.0 To: linux-media@vger.kernel.org Subject: [PATCH] DVB: stb0899: speed up getting BER values X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0.1 (racoon.tvdr.de [188.40.50.18]); Sat, 02 Jun 2012 17:05:05 +0200 (CEST) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-PMX-Version: 5.6.1.2065439, Antispam-Engine: 2.7.2.376379, Antispam-Data: 2012.6.2.150315 X-PMX-Spam: Gauge=IIIIIIII, Probability=8%, Report=' HTML_00_01 0.05, HTML_00_10 0.05, MIME_TEXT_ONLY_MP_MIXED 0.05, MSGID_ADDED_BY_MTA 0.05, BODYTEXTP_SIZE_3000_LESS 0, BODY_SIZE_2000_2999 0, BODY_SIZE_5000_LESS 0, BODY_SIZE_7000_LESS 0, URI_ENDS_IN_HTML 0, __ANY_URI 0, __BAT_BOUNDARY 0, __CP_URI_IN_BODY 0, __CT 0, __CTYPE_HAS_BOUNDARY 0, __CTYPE_MULTIPART 0, __CTYPE_MULTIPART_MIXED 0, __HAS_MSGID 0, __HAS_X_MAILING_LIST 0, __MIME_TEXT_ONLY 0, __MIME_VERSION 0, __MOZILLA_MSGID 0, __SANE_MSGID 0, __SUBJ_ALPHA_END 0, __TO_MALFORMED_2 0, __TO_NO_NAME 0, __URI_NO_WWW 0, __URI_NS , __USER_AGENT 0' stb0899_read_ber() takes 500ms (half a second!) to deliver the current BER value. Apparently it takes 5 subsequent readings, with a 100ms pause between them (and even before the first one). This is a real performance brake if an application freqeuently reads the BER of several devices. The attached patch reduces this to a single reading, with no more pausing. I didn't observe any negative side effects of this change. Signed-off-by: Klaus Schmidinger Klaus --- a/linux/drivers/media/dvb/frontends/stb0899_drv.c 2012-04-23 15:10:35.994008188 +0200 +++ a/linux/drivers/media/dvb/frontends/stb0899_drv.c 2012-04-23 15:29:40.544837905 +0200 @@ -1135,7 +1135,6 @@ struct stb0899_internal *internal = &state->internal; u8 lsb, msb; - u32 i; *ber = 0; @@ -1143,14 +1142,9 @@ case SYS_DVBS: case SYS_DSS: if (internal->lock) { - /* average 5 BER values */ - for (i = 0; i < 5; i++) { - msleep(100); - lsb = stb0899_read_reg(state, STB0899_ECNT1L); - msb = stb0899_read_reg(state, STB0899_ECNT1M); - *ber += MAKEWORD16(msb, lsb); - } - *ber /= 5; + lsb = stb0899_read_reg(state, STB0899_ECNT1L); + msb = stb0899_read_reg(state, STB0899_ECNT1M); + *ber = MAKEWORD16(msb, lsb); /* Viterbi Check */ if (STB0899_GETFIELD(VSTATUS_PRFVIT, internal->v_status)) { /* Error Rate */ @@ -1163,13 +1157,9 @@ break; case SYS_DVBS2: if (internal->lock) { - /* Average 5 PER values */ - for (i = 0; i < 5; i++) { - msleep(100); - lsb = stb0899_read_reg(state, STB0899_ECNT1L); - msb = stb0899_read_reg(state, STB0899_ECNT1M); - *ber += MAKEWORD16(msb, lsb); - } + lsb = stb0899_read_reg(state, STB0899_ECNT1L); + msb = stb0899_read_reg(state, STB0899_ECNT1M); + *ber = MAKEWORD16(msb, lsb); /* ber = ber * 10 ^ 7 */ *ber *= 10000000; *ber /= (-1 + (1 << (4 + 2 * STB0899_GETFIELD(NOE, internal->err_ctrl))));