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Re: uvideo webcam on big-endian systems



Hi Frank,

On Thu, 2010-12-09 at 11:22 +0100, Frank Wille wrote:
> Was the driver ever tested on big-endian systems? Could there be a bug?

I don't believe uvideo has been used on anything other than i386/amd64,
so it's quite possible that there's an endian fault.

> I just skimmed over the source of video.c and uvideo.c without
> understanding it, but maybe there has to be an endian-conversion in
> buf32tobuf() and buftobuf32() of video.c?

As I understand it, those are related to COMPAT32 and handle the
situation where a 32-bit process is running under a 64-bit kernel (i.e.
some ABI incompatibilities).

The most likely place for a problem to occur is in uvideo.c, where
control data gets packed/unpacked to/from structs that go to USB.

Could you recompile with options UVIDEO_DEBUG and VIDEO_DEBUG, then send
the relevant portions of dmesg? Those tend to dump a lot of descriptor
data, which might reveal any fields that haven't been correctly swapped.

--
Thanks,
Jeremy

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