Re: Problems using quickcam_messenger on ARM (FYI)

From: Markus Hirschmann
Date: Tue Nov 13 2007 - 16:36:23 EST


Hi Thierry

Thierry Merle wrote:
Hi Mauro,
Mauro Carvalho Chehab a Ãcrit :
Em Ter, 2007-11-06 Ãs 18:25 +0100, Markus Hirschmann escreveu:
Hello Kernel-Developer,

Module quickcam_messenger seems to be broken (tried 2.6.18 and 2.6.22)
on 2 different NSLU2 (ARM). Picture is attached. Same kernel and module can be used without any problems on x86 here. I don't have any ARM device beside the NSLU2, so I cannot check.

The solution was to use Christian Magnusson's quickcam module. Everything worked without any problem. Webcam is:
Hmm... you're mentioning the quickcam module, but some of your logs are
related to usbvideo driver.

On a quick glance, I didn't find anything that could explain your
troubles. It seems to be related to a wrong order at the output format
(for example, the driver is sending RGB, instead of BGR).

It may also be an issue at the userspace application that is using the
wrong logic to deal with Big Endian.

The NSLU2 is based on a IXP420 processor that can change its endianess.
I suppose Markus has installed the debian-arm distribution on his NSLU2
so it is configured as little-endian.
Nevertheless, I took a look at the code of quickcam messenger that is in
usbvideo/
This macro: RGB24_PUTPIXEL puts in memory the following bytes:
*pf++ = (vb);
*pf++ = (vg);
*pf++ = (vr);
vb, vg, vr are blue, green, red values.
Since the driver is still v4l1 this can be normal(?)

Right, I forgot. Installed is the Debian ARM distribution. And I tried serveral different applications (motion, vgrabbj).

Best regards

Markus
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