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Date: Wed, 11 Aug 2010 14:31:56 -0400
Message-ID: <AANLkTin7JxN81tpM+=rmN6jjnOBkd6c+Cy9tx5vruSZ7@mail.gmail.com>
Subject: Re: [2.6.35] usb 2.0 em28xx kernel panic general protection fault: 
	0000 [#1] SMP RIP: 0010:[<ffffffffa004fbc5>] [<ffffffffa004fbc5>] 
	em28xx_isoc_copy_vbi+0x62e/0x812 [em28xx]
From: Devin Heitmueller <dheitmueller@kernellabs.com>
To: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Pete Eberlein <pete@sensoray.com>,
        Sander Eikelenboom <linux@eikelenboom.it>, mrechberger@gmail.com,
        gregkh@suse.de, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org, linux-usb@vger.kernel.org
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On Wed, Aug 11, 2010 at 12:46 PM, Mauro Carvalho Chehab
<mchehab@infradead.org> wrote:
> Em 11-08-2010 12:58, Pete Eberlein escreveu:
>> On Wed, 2010-08-11 at 09:25 +0200, Sander Eikelenboom wrote:
>>> Hello Devin,
>>>
>>> Yes it's completely reproducible for a change:
>>>
>>> ffmpeg -f video4linux -r 25 -s 720x576 -i /dev/video0 out.flv
>>> gave an error:
>>
>> Use -f video4linux2.
>>
>> The -f video4linux option uses the old video4linux1 API. ?I have seen
>> similar strange behavior when I used that ffmpeg option with a v4l2
>> driver I am developing. ?Also, ffmpeg does not use libv4l.
>
> Still, we have a bug to fix. The driver shouldn't generating a PANIC if accessed
> via V4L1 API.

I agree with Mauro completely.  There is nothing userland should be
able to do which results in a panic (and I have no reason to believe
Pete was suggesting otherwise).  That said, it's really useful to know
that this is some sort of v4l1 backward compatibility problem.

I'll see if I can reproduce this here.

Thanks,

Devin

-- 
Devin J. Heitmueller - Kernel Labs
http://www.kernellabs.com
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