Received-SPF: pass (google.com: domain of linux-kernel+bounces-116673-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
Precedence: bulk
MIME-Version: 1.0
References: <20240323-resend-hwtimestamp-v10-0-b08e590d97c7@chromium.org>
 <20240323-resend-hwtimestamp-v10-3-b08e590d97c7@chromium.org> <2722561.mvXUDI8C0e@natalenko.name>
In-Reply-To: <2722561.mvXUDI8C0e@natalenko.name>
From: Ricardo Ribalda <ribalda@chromium.org>
Date: Mon, 25 Mar 2024 08:52:57 +0100
Message-ID: <CANiDSCsnOdTaW0Eg68+-niPXwPhYc3Br6cWoGiHytZrFOGmcZA@mail.gmail.com>
Subject: Re: [PATCH v10 3/6] media: uvcvideo: Quirk for invalid dev_sof in
 Logitech C922
To: Oleksandr Natalenko <oleksandr@natalenko.name>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>, 
	Mauro Carvalho Chehab <mchehab@kernel.org>, linux-media@vger.kernel.org, 
	linux-kernel@vger.kernel.org, "hn.chen" <hn.chen@sunplusit.com>, 
	Hans Verkuil <hverkuil@xs4all.nl>, Sergey Senozhatsky <senozhatsky@chromium.org>
Content-Type: text/plain; charset="UTF-8"

Hi Oleksandr

On Sat, 23 Mar 2024 at 13:16, Oleksandr Natalenko
<oleksandr@natalenko.name> wrote:

>
> How do I check whether C920 (046d:082d) is affected too? I have got one, I can run tests on it as long as those will not blow the webcam up.
>
> Thanks.
>

First of all you need to enable the hwtimestamps in the driver. You
could do that with

```
rmmod uvcvideo; modprobe uvcvideo hwtimestamps=1
```

Then capture some frames with yavta
```
yavta -c /dev/video0
```

After around 5 seconds all the frames should have a stable fps, the
fps is not stable then your camera is affected with this bug.


Thanks!