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From: Hans Verkuil <>
To: Gregor Jasny <>,,,
	Linux Media Mailing List <>
Subject: Re: Bug#929262: libv4l-dev: pac207 cam(s) give frame decode errors
Date: Mon, 20 May 2019 13:55:35 +0200
Message-ID: <> (raw)
In-Reply-To: <>

On 5/20/19 1:38 PM, Gregor Jasny wrote:
> Hello,
> On 20.05.19 10:25, wrote:
>> Trying to get a pac207 camera to work with constatus.
>> 2019-05-20 10:22:34.864900  INFO constatus [1-1] source v4l2 thread started
>> libv4l2: error got 4 consecutive frame decode errors, last error: v4l-convert: error unknown pac207 row header: 0x0000
>> 2019-05-20 10:22:35.597949 ERROR cs:src_v4l2 [1-1] VIDIOC_DQBUF failed: Input/output error
>> ioctl(VIDIOC_QBUF) failed
>> errno: 22 (Invalid argument)
>> To verify that it is not a constatus-problem I also tried a raspberry-pi camera via its video4linux-interface and that works fine.
> According to the Linux Kernel Maintainers file the device driver is 
> maintained by Hans, which I CC'ed on this bug report:
> M:	Hans Verkuil <>
> L:
> T:	git git://
> S:	Odd Fixes
> F:	drivers/media/usb/gspca/pac207.c
> Did your camera ever work on another Kernel, CPU architecture, or 
> v4l-utils version? Do you have anything suspicious in dmesg output?

I strongly recommend that you buy a new webcam. This is ancient hardware.
Even the cheapest UVC webcams you can buy today will have far better
quality than a pac207. If you really, really need this to work, then I
need the full dmesg output and you also need to check if you can reproduce
this issue with the v4l2-ctl command:

v4l2-ctl -d /dev/videoX --stream-mmap

(it keeps capturing frames until you press ctrl-X)

I should have one of these webcams, but won't be able to test until next



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Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <155834073601.757.12828508994068038463.reportbug@scrollert>
2019-05-20 11:38 ` Gregor Jasny
2019-05-20 11:55   ` Hans Verkuil [this message]
2019-05-20 19:23     ` folkert

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