From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E60D017ADF0; Mon, 26 Aug 2024 12:36:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724675776; cv=none; b=CluFKULTmPV01s3bB4qTTb5YDOqu3S1ygnOTl5ElGA467/C77ri+MJ+lBjQL5CSdJqW7+QYJxZxwqjzIvSQ9IcN1hGZVCFb+L4dSGlFuY4cw8gbVpJBG6XbF57MmdtycNI4YupmxiHqGQm24tLLe8Gz1Nf0aAdjmWmh+dlNNDpw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724675776; c=relaxed/simple; bh=vPGZN81hK5OAKrdCJfVnYxzu0eIEohW+niVzaqHRGys=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=NoTZPjDQinLJ+o2izvLVrUTFDFIZ1Hi7z0cXUCQtcICv5gOaV+C4HB+zMb8NyH/L/42Z4NoacFP5J75JSPG0EkIhtfjAwVGfkDdW2xyMFukxBCBIuPmTpHgFbc3rpxwqf0xNBjbTwymWzKj7JA2nL/ykrGFiAyjOUL6C12WKKx4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=am4/BUFh; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="am4/BUFh" Received: from [192.168.88.20] (91-156-87-48.elisa-laajakaista.fi [91.156.87.48]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 857036CA; Mon, 26 Aug 2024 14:35:06 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1724675707; bh=vPGZN81hK5OAKrdCJfVnYxzu0eIEohW+niVzaqHRGys=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=am4/BUFhsfvPbnJKVsm4WVr2/6HquzH6IZvOL/2VqrHIRWYOYoQ7E6RvSBaSnHIHZ tWd0VfHmxBvg5Cb0xh6W53fD9R3tUiYiuYMri4sx+38z9kwvCPVIsRRZqBvEy2eMt1 0ifyK8qqjrYf7UlEcTF+2KkifroSzpUZScsSQf0g= Message-ID: Date: Mon, 26 Aug 2024 15:36:10 +0300 Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 7/7] [DNI] media: renesas: vsp1: Validate all links through .link_validate() To: Laurent Pinchart Cc: linux-media@vger.kernel.org, Chen-Yu Tsai , Eugen Hristev , Hans Verkuil , Jacopo Mondi , Kieran Bingham , Maxime Ripard , Sakari Ailus , linux-renesas-soc@vger.kernel.org, linux-sunxi@lists.linux.dev References: <20240822154531.25912-1-laurent.pinchart+renesas@ideasonboard.com> <20240822154531.25912-8-laurent.pinchart+renesas@ideasonboard.com> <93fd78a6-c8fa-421f-b10c-69a42ac8112d@ideasonboard.com> <20240826121835.GE27785@pendragon.ideasonboard.com> <20240826122553.GF27785@pendragon.ideasonboard.com> Content-Language: en-US From: Tomi Valkeinen Autocrypt: addr=tomi.valkeinen@ideasonboard.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 26/08/2024 15:25, Laurent Pinchart wrote: > On Mon, Aug 26, 2024 at 03:22:02PM +0300, Tomi Valkeinen wrote: >> On 26/08/2024 15:18, Laurent Pinchart wrote: >>> Hi Tomi, >>> >>> On Mon, Aug 26, 2024 at 02:43:47PM +0300, Tomi Valkeinen wrote: >>>> On 22/08/2024 18:45, Laurent Pinchart wrote: >>>>> Move validation of the links between video devices and subdevs, >>>>> performed manually in vsp1_video_streamon(), to the video device >>>>> .link_validate() handler. >>>>> >>>>> This is how drivers should be implemented, but sadly, doing so for the >>>>> vsp1 driver could break userspace, introducing a regression. This patch >>>>> serves as an example to showcase usage of the .link_validate() >>>>> operation, but should not be merged. >>>>> >>>>> Signed-off-by: Laurent Pinchart >>>>> --- >>>>> .../media/platform/renesas/vsp1/vsp1_video.c | 98 +++++++------------ >>>>> 1 file changed, 37 insertions(+), 61 deletions(-) >>>>> >>>>> diff --git a/drivers/media/platform/renesas/vsp1/vsp1_video.c b/drivers/media/platform/renesas/vsp1/vsp1_video.c >>>>> index e728f9f5160e..14575698bbe7 100644 >>>>> --- a/drivers/media/platform/renesas/vsp1/vsp1_video.c >>>>> +++ b/drivers/media/platform/renesas/vsp1/vsp1_video.c >>>>> @@ -45,51 +45,6 @@ >>>>> * Helper functions >>>>> */ >>>>> >>>>> -static struct v4l2_subdev * >>>>> -vsp1_video_remote_subdev(struct media_pad *local, u32 *pad) >>>>> -{ >>>>> - struct media_pad *remote; >>>>> - >>>>> - remote = media_pad_remote_pad_first(local); >>>>> - if (!remote || !is_media_entity_v4l2_subdev(remote->entity)) >>>>> - return NULL; >>>>> - >>>>> - if (pad) >>>>> - *pad = remote->index; >>>>> - >>>>> - return media_entity_to_v4l2_subdev(remote->entity); >>>>> -} >>>>> - >>>>> -static int vsp1_video_verify_format(struct vsp1_video *video) >>>>> -{ >>>>> - struct v4l2_subdev_format fmt = { >>>>> - .which = V4L2_SUBDEV_FORMAT_ACTIVE, >>>>> - }; >>>>> - struct v4l2_subdev *subdev; >>>>> - int ret; >>>>> - >>>>> - subdev = vsp1_video_remote_subdev(&video->pad, &fmt.pad); >>>>> - if (subdev == NULL) >>>>> - return -EINVAL; >>>>> - >>>>> - ret = v4l2_subdev_call(subdev, pad, get_fmt, NULL, &fmt); >>>>> - if (ret < 0) >>>>> - return ret == -ENOIOCTLCMD ? -EINVAL : ret; >>>>> - >>>>> - if (video->rwpf->fmtinfo->mbus != fmt.format.code || >>>>> - video->rwpf->format.height != fmt.format.height || >>>>> - video->rwpf->format.width != fmt.format.width) { >>>>> - dev_dbg(video->vsp1->dev, >>>>> - "Format mismatch: 0x%04x/%ux%u != 0x%04x/%ux%u\n", >>>>> - video->rwpf->fmtinfo->mbus, video->rwpf->format.width, >>>>> - video->rwpf->format.height, fmt.format.code, >>>>> - fmt.format.width, fmt.format.height); >>>>> - return -EPIPE; >>>>> - } >>>>> - >>>>> - return 0; >>>>> -} >>>>> - >>>>> static int __vsp1_video_try_format(struct vsp1_video *video, >>>>> struct v4l2_pix_format_mplane *pix, >>>>> const struct vsp1_format_info **fmtinfo) >>>>> @@ -991,14 +946,6 @@ vsp1_video_streamon(struct file *file, void *fh, enum v4l2_buf_type type) >>>>> >>>>> mutex_unlock(&mdev->graph_mutex); >>>>> >>>>> - /* >>>>> - * Verify that the configured format matches the output of the connected >>>>> - * subdev. >>>>> - */ >>>>> - ret = vsp1_video_verify_format(video); >>>>> - if (ret < 0) >>>>> - goto err_stop; >>>>> - >>>>> /* Start the queue. */ >>>>> ret = vb2_streamon(&video->queue, type); >>>>> if (ret < 0) >>>>> @@ -1087,14 +1034,43 @@ static const struct v4l2_file_operations vsp1_video_fops = { >>>>> >>>>> static int vsp1_video_link_validate(struct media_link *link) >>>>> { >>>>> - /* >>>>> - * Ideally, link validation should be implemented here instead of >>>>> - * calling vsp1_video_verify_format() in vsp1_video_streamon() >>>>> - * manually. That would however break userspace that start one video >>>>> - * device before configures formats on other video devices in the >>>>> - * pipeline. This operation is just a no-op to silence the warnings >>>>> - * from v4l2_subdev_link_validate(). >>>>> - */ >>>>> + struct v4l2_subdev_format fmt = { >>>>> + .which = V4L2_SUBDEV_FORMAT_ACTIVE, >>>>> + }; >>>>> + struct v4l2_subdev *subdev; >>>>> + struct media_entity *entity; >>>>> + struct media_pad *remote; >>>>> + struct vsp1_video *video; >>>>> + int ret; >>>>> + >>>>> + if (is_media_entity_v4l2_video_device(link->source->entity)) { >>>>> + entity = link->source->entity; >>>>> + remote = link->sink; >>>>> + } else { >>>>> + entity = link->sink->entity; >>>>> + remote = link->source; >>>>> + } >>>> >>>> This looks a bit odd. So this device can be either a source and a sink? >>> >>> Correct. The VSP has both capture and output video devices, and this >>> helper function is used for both. >>> >>>> This made me also wonder about the .link_validate(). It's the only >>>> media_entity_operations op that does not get the media_entity as a >>>> parameter. Which here means the driver has to go and "guess" whether it >>>> is the source or the sink of the given link. >>>> >>>> I wonder if there's a reason why .link_validate() doesn't have the >>>> media_entity parameter? >>> >>> Because it validates a link. Which of the sink or source entity would >>> you pass to the function ? >> >> The one where the op is defined. > > With the exception of links from video output devices to subdevs, it's > always the sink. I don't expect most drivers to use a single validation > function for the capture and output video devices, so I don't think > passing the entity pointer is that crucial. We could however improve > this on top in case it ends up being a common use case. It's an issue even if the driver only acts as a sink or source, but I agree, not crucial at all. Looking at the patch 1 of this series: +static int isc_link_validate(struct media_link *link) { + struct video_device *vdev = + media_entity_to_video_device(link->sink->entity); that should be: static int isc_link_validate(struct media_entity *ent, struct media_link *link) { struct video_device *vdev = media_entity_to_video_device(ent); In any case, that's a topic for another series =). Tomi