AW: AW: v4l2_buffer with PBO mapped memory

[Scheuermann, Mail]

Hi Laurent,

I've done the following:

echo 3 >/sys/module/videobuf2_core/parameters/debug

and found in /var/log/kern.log after starting my program:

Apr  4 21:53:48 x240 kernel: [239432.535077] vb2: Buffer 0, plane 0 offset 
0x
Apr  4 21:53:48 x240 kernel: [239432.535080] vb2: Buffer 1, plane 0 offset 
0x001c2000
Apr  4 21:53:48 x240 kernel: [239432.535082] vb2: Buffer 2, plane 0 offset 
0x00384000
Apr  4 21:53:48 x240 kernel: [239432.535083] vb2: Allocated 3 buffers, 1 
plane(s) each
Apr  4 21:53:48 x240 kernel: [239432.535085] vb2: qbuf: userspace address for 
plane 0 changed, reacquiring memory
Apr  4 21:53:48 x240 kernel: [239432.535087] vb2: qbuf: failed acquiring 
userspace memory for plane 0
Apr  4 21:53:48 x240 kernel: [239432.535088] vb2: qbuf: buffer preparation 
failed: -22
Apr  4 21:53:48 x240 kernel: [239432.535128] vb2: streamoff: not streaming

Regards,

Thomas


Von: Laurent Pinchart [laurent.pinch...@ideasonboard.com]
Gesendet: Freitag, 4. April 2014 01:16
An: Scheuermann, Mail
Cc: linux-media@vger.kernel.org
Betreff: Re: AW: v4l2_buffer with PBO mapped memory

Hi Thomas,

On Thursday 03 April 2014 16:52:19 Scheuermann, Mail wrote:
> Hi Laurent,
>
> the driver my device uses is the uvcvideo. I have the kernel 3.11.0-18 from
> Ubuntu 13.10 running. It is built in in a Thinkpad X240 notebook.

OK. A bit of debugging will then be needed. Could you set the videobuf2-core
debug parameter to 3, retry your test case and send us the kernel log ?

--
Regards,

Laurent Pinchart

This message is subject to the following terms and conditions: MAIL 
DISCLAIMER<http://www.barco.com/en/maildisclaimer>
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

AW: v4l2_buffer with PBO mapped memory

[Scheuermann, Mail]

Hi Laurent,

the driver my device uses is the uvcvideo. I have the kernel 3.11.0-18 from 
Ubuntu 13.10 running.
It is built in in a Thinkpad X240 notebook.

Regards,

Thomas


Von: Laurent Pinchart [laurent.pinch...@ideasonboard.com]
Gesendet: Mittwoch, 2. April 2014 21:23
An: Scheuermann, Mail
Cc: linux-media@vger.kernel.org
Betreff: Re: v4l2_buffer with PBO mapped memory

Hi Thomas,

On Wednesday 02 April 2014 17:10:42 Thomas Scheuermann wrote:
> Hello,
>
> I've written a program which shows my webcam with the v4l2 interface.
> In the v4l2_buffer I use the type V4L2_BUF_TYPE_VIDEO_CAPTURE and the
> memory is V4L2_MEMORY_USERPTR.
> Everything works if I use malloced memory for frame buffers.
> Now I want to get the frames directly in OpenGL. I've mapped a pixel
> buffer object with glMapBuffer and wanted to use this as a frame buffer.
> But if I use this memory, the ioctl VIDIOC_QBUF fails with 'invalid
> argument'.
>
> What can I do to use the pixel buffer object together with the v4l2
> interface?
> I want to use as less copy steps as possible.

The use case is reasonable (although V4L2_MEMORY_DMABUF would be better, but
we're not there yet on the OpenGL side I believe), so let's try to debug this.
First of all, what webcam driver do you use ?

--
Regards,

Laurent Pinchart

This message is subject to the following terms and conditions: MAIL 
DISCLAIMER<http://www.barco.com/en/maildisclaimer>
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html