Re: Problems using quickcam_messenger on ARM (FYI)

[Thierry Merle]

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(?)

Cheers,
Thierry
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