From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56CF1C282DC for ; Sun, 7 Apr 2019 03:21:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3201520B1F for ; Sun, 7 Apr 2019 03:21:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726556AbfDGDVN (ORCPT ); Sat, 6 Apr 2019 23:21:13 -0400 Received: from www.osadl.org ([62.245.132.105]:39362 "EHLO www.osadl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726468AbfDGDVM (ORCPT ); Sat, 6 Apr 2019 23:21:12 -0400 X-Greylist: delayed 3874 seconds by postgrey-1.27 at vger.kernel.org; Sat, 06 Apr 2019 23:21:06 EDT Received: from localhost.localdomain (178.115.242.59.static.drei.at [178.115.242.59]) by www.osadl.org (8.13.8/8.13.8/OSADL-2007092901) with ESMTP id x372GCs0021361; Sun, 7 Apr 2019 04:16:12 +0200 From: Nicholas Mc Guire To: Sakari Ailus Cc: Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Nicholas Mc Guire Subject: [PATCH 1/3] media: smiapp: core: add range to usleep_range Date: Sun, 7 Apr 2019 04:16:02 +0200 Message-Id: <1554603364-10500-1-git-send-email-hofrat@opentech.at> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Allow the hrtimer subsystem to coalesce delay timers of lower accuracy by providing a suitable range Signed-off-by: Nicholas Mc Guire --- Problem located by an experimental coccinelle script hrtimers in atomic context have limited accuracy due to possible context-switching and interruption so the accuracy is limited anyway. Giving the hrtimer subsystem a reasonable range for merging hrtimers helps to reduce the load on the hrtimer subsystem. As this delays do not seem to mandate high accuracy the range of a factor two seems acceptable. Patch was compile tested with: x86_64_defconfig + MEDIA_SUPPORT=m, MEDIA_CAMERA_SUPPORT=y, MEDIA_CONTROLLER=y, VIDEO_V4L2_SUBDEV_API=y, VIDEO_SMIAPP=m (with a number of sparse warnings on sizeof() usage) Patch is against 5.1-rc3 (localversion-next is next-20190405) drivers/media/i2c/smiapp/smiapp-core.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/media/i2c/smiapp/smiapp-core.c b/drivers/media/i2c/smiapp/smiapp-core.c index 58a45c3..c0c29ec 100644 --- a/drivers/media/i2c/smiapp/smiapp-core.c +++ b/drivers/media/i2c/smiapp/smiapp-core.c @@ -1222,19 +1222,19 @@ static int smiapp_power_on(struct device *dev) dev_err(&client->dev, "failed to enable vana regulator\n"); return rval; } - usleep_range(1000, 1000); + usleep_range(1000, 2000); rval = clk_prepare_enable(sensor->ext_clk); if (rval < 0) { dev_dbg(&client->dev, "failed to enable xclk\n"); goto out_xclk_fail; } - usleep_range(1000, 1000); + usleep_range(1000, 2000); gpiod_set_value(sensor->xshutdown, 1); sleep = SMIAPP_RESET_DELAY(sensor->hwcfg->ext_clk); - usleep_range(sleep, sleep); + usleep_range(sleep, sleep*2); mutex_lock(&sensor->mutex); @@ -1381,7 +1381,7 @@ static int smiapp_power_off(struct device *dev) gpiod_set_value(sensor->xshutdown, 0); clk_disable_unprepare(sensor->ext_clk); - usleep_range(5000, 5000); + usleep_range(5000, 10000); regulator_disable(sensor->vana); sensor->streaming = false; -- 2.1.4