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Sender: Guenter Roeck <groeck7@gmail.com>
Subject: Re: [PATCH RESEND v3 0/5] media: uvcvideo: Fix race conditions
To:     Dominique MARTINET <dominique.martinet@atmark-techno.com>
Cc:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Sakari Ailus <sakari.ailus@iki.fi>,
        linux-uvc-devel@lists.sourceforge.net, linux-usb@vger.kernel.org,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
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From:   Guenter Roeck <linux@roeck-us.net>
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Date:   Fri, 12 Mar 2021 06:54:52 -0800
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On 3/11/21 11:36 PM, Dominique MARTINET wrote:
> Hi,
> 
> Guenter Roeck wrote on Thu, Sep 17, 2020 at 07:16:17PM -0700:
>> On 9/17/20 5:47 AM, Laurent Pinchart wrote:
>>> On Wed, Sep 16, 2020 at 07:25:42PM -0700, Guenter Roeck wrote:
>>>> Something seems to have gone wrong with v3 of this patch series.
>>>> I am sure I sent it out, but I don't find it anywhere.
>>>> Resending. Sorry for any duplicates.
>>>
>>> I haven't checked the mailing list, but I've found it in my inbox :-)
>>> I'm not forgetting about you, just been fairly busy recently. I still
>>> plan to try and provide an alternative implementation in the V4L2 core
>>> (in a form that I think should even be moved to the cdev core) that
>>> would fix this for all drivers.
>>>
>> Thanks for letting me know. As it turns out, this problem is responsible
>> for about 2% of all Chromebook crashes, so I'll probably not wait for
>> the series to be accepted upstream but apply it as-is to the various
>> ChromeOS kernel branches.
> 
> We have a customer who reported the same issue recently, has there been
> any development?
> 

Not that I know of. We applied the series to all Chrome OS kernel branches,
and it reliably fixes the problem for us. We'd like to have the problem
fixed upstream; until that happens we'll have to carry the series forward.

> I don't see anything in either uvc nor v4l2 that would address the race
> since this mail half a year ago (well, I could have missed it ;))
> 

The problem still exists in the upstream kernel.

Guenter