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=-18.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 530D9C433ED for ; Wed, 5 May 2021 10:57:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1B97961168 for ; Wed, 5 May 2021 10:57:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232319AbhEEK6B (ORCPT ); Wed, 5 May 2021 06:58:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:38552 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231431AbhEEK6B (ORCPT ); Wed, 5 May 2021 06:58:01 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4D1F5613C1; Wed, 5 May 2021 10:57:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1620212225; bh=q2rfGosiUXnzr4dF55bRgXbsz6DIXhywXMGLl103om8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=t/9ezzcKX4IEKiMjOXyDomtU8/Byb/0KpfuxIm+Ti/5dRkMrGyEJvvbvJI20Cgdvs IjEJIfcbfSIPH/ZKcamlare8lBqhHKYwV6vys7AY239Vqx6GhrQ8cV4zRWVdMy3VUS xGpHfHLdIElkCQaQTkkthrhJgJUQQb9eP9m4EzlZMAqDhMgF+vDclfkkpo5kpF2WdJ 8E3btr8K92tWfGINo538k8sO5VkO1w+IWtWnYUnKQtkevdp9s2mrw7lfTIXxuWnl8C jXsS+z+pB3zgDqF0hihKfcVzn3xs3RuUeuCsE/t2GNBnz1qK42cgXOyEHqGPrImT3G 1DgYbl8gyE+Cw== Date: Wed, 5 May 2021 12:57:00 +0200 From: Mauro Carvalho Chehab To: Sakari Ailus Cc: linuxarm@huawei.com, mauro.chehab@huawei.com, Mauro Carvalho Chehab , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org Subject: Re: [PATCH 25/25] media: i2c: ccs-core: fix pm_runtime_get_sync() usage count Message-ID: <20210505125700.4a7584ca@coco.lan> In-Reply-To: <20210505103409.GN3@paasikivi.fi.intel.com> References: <83ec24acb15f17e2ce589575c2f5eb7bdd1daf28.1620207353.git.mchehab+huawei@kernel.org> <20210505103409.GN3@paasikivi.fi.intel.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Em Wed, 5 May 2021 13:34:09 +0300 Sakari Ailus escreveu: > Hi Mauro, > > Thanks for the patch. > > On Wed, May 05, 2021 at 11:42:15AM +0200, Mauro Carvalho Chehab wrote: > > The pm_runtime_get_sync() internally increments the > > dev->power.usage_count without decrementing it, even on errors. > > > > There is a bug at ccs_pm_get_init(): when this function returns > > an error, the stream is not started, and RPM usage_count > > should not be incremented. However, if the calls to > > v4l2_ctrl_handler_setup() return errors, it will be kept > > incremented. > > > > At ccs_suspend() the best is to replace it by the new > > pm_runtime_resume_and_get(), introduced by: > > commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter") > > in order to properly decrement the usage counter automatically, > > in the case of errors. > > > > Signed-off-by: Mauro Carvalho Chehab > > Could you add Fixes: line and Cc: stable? Sure. See the fixes one enclosed. > The patch that breaks this is 96e3a6b92f23a . > > It would be better to fix the bug first so the patch to the stable trees > doesn't need special handling. > > > --- > > drivers/media/i2c/ccs/ccs-core.c | 39 ++++++++++++++++++++------------ > > 1 file changed, 24 insertions(+), 15 deletions(-) > > > > diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c > > index b05f409014b2..04c3ab9e37b4 100644 > > --- a/drivers/media/i2c/ccs/ccs-core.c > > +++ b/drivers/media/i2c/ccs/ccs-core.c > > @@ -1880,21 +1880,33 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor) > > struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd); > > int rval; > > > > + /* > > + * It can't use pm_runtime_resume_and_get() here, as the driver > > + * relies at the returned value to detect if the device was already > > + * active or not. > > + */ > > rval = pm_runtime_get_sync(&client->dev); > > - if (rval < 0) { > > - pm_runtime_put_noidle(&client->dev); > > + if (rval < 0) > > + goto error; > > > > - return rval; > > - } else if (!rval) { > > - rval = v4l2_ctrl_handler_setup(&sensor->pixel_array-> > > - ctrl_handler); > > - if (rval) > > - return rval; > > + /* Device was already active, so don't set controls */ > > + if (rval == 1) > > + return 0; > > > > - return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler); > > - } > > + /* Restore V4L2 controls to the suspended device */ > > + rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->ctrl_handler); > > + if (rval) > > + goto error; > > > > + rval = v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler); > > + if (rval) > > + goto error; > > + > > + /* Keep PM runtime usage_count incremented on success */ > > return 0; > > +error: > > + pm_runtime_put_noidle(&client->dev); > > This needs to be pm_runtime_put() as the device has been successfully. Ok. > > > + return rval; > > } > > > > static int ccs_set_stream(struct v4l2_subdev *subdev, int enable) > > @@ -3089,12 +3101,9 @@ static int __maybe_unused ccs_suspend(struct device *dev) > > bool streaming = sensor->streaming; > > int rval; > > > > - rval = pm_runtime_get_sync(dev); > > - if (rval < 0) { > > - pm_runtime_put_noidle(dev); > > - > > + rval = pm_runtime_resume_and_get(dev); > > + if (rval < 0) > > return rval; > > - } > > > > if (sensor->streaming) > > ccs_stop_streaming(sensor); > Thanks, Mauro --- [PATCH] media: i2c: ccs-core: fix pm_runtime_get_sync() usage count The pm_runtime_get_sync() internally increments the dev->power.usage_count without decrementing it, even on errors. There is a bug at ccs_pm_get_init(): when this function returns an error, the stream is not started, and RPM usage_count should not be incremented. However, if the calls to v4l2_ctrl_handler_setup() return errors, it will be kept incremented. At ccs_suspend() the best is to replace it by the new pm_runtime_resume_and_get(), introduced by: commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter") in order to properly decrement the usage counter automatically, in the case of errors. Fixes: 96e3a6b92f23 ("media: smiapp: Avoid maintaining power state information") Cc: stable@vger.kernel.org Signed-off-by: Mauro Carvalho Chehab diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c index b05f409014b2..5ea471fefa3a 100644 --- a/drivers/media/i2c/ccs/ccs-core.c +++ b/drivers/media/i2c/ccs/ccs-core.c @@ -1880,21 +1880,33 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor) struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd); int rval; + /* + * It can't use pm_runtime_resume_and_get() here, as the driver + * relies at the returned value to detect if the device was already + * active or not. + */ rval = pm_runtime_get_sync(&client->dev); - if (rval < 0) { - pm_runtime_put_noidle(&client->dev); + if (rval < 0) + goto error; - return rval; - } else if (!rval) { - rval = v4l2_ctrl_handler_setup(&sensor->pixel_array-> - ctrl_handler); - if (rval) - return rval; + /* Device was already active, so don't set controls */ + if (rval == 1) + return 0; - return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler); - } + /* Restore V4L2 controls to the suspended device */ + rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->ctrl_handler); + if (rval) + goto error; + rval = v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler); + if (rval) + goto error; + + /* Keep PM runtime usage_count incremented on success */ return 0; +error: + pm_runtime_put(&client->dev); + return rval; } static int ccs_set_stream(struct v4l2_subdev *subdev, int enable)