Re: [PATCH] usbvision: remove (broken) image format conversion

[Hans de Goede]

Hi,

On 04/26/2011 10:30 AM, Ondrej Zary wrote:
> On Tuesday 26 April 2011, you wrote:
> > On Monday, April 25, 2011 23:23:17 Ondrej Zary wrote:
> > > The YVU420 and YUV422P formats are broken and cause kernel panic on use.
> > > (YVU420 does not work and sometimes causes "unable to handle paging
> > > request" panic, YUV422P always causes "NULL pointer dereference").
> > >
> > > As V4L2 spec says that drivers shouldn't do any in-kernel image format
> > > conversion, remove it completely (except YUYV).
> >
> > What really should happen is that the conversion is moved to libv4lconvert.
> > I've never had the time to tackle that, but it would improve this driver a
> > lot.
>
> Depending on isoc_mode module parameter, the device uses different image
> formats: YUV 4:2:2 interleaved, YUV 4:2:0 planar or compressed format.
>
> Maybe the parameter should go away and these three formats exposed to
> userspace?

That sounds right,

> Hopefully the non-compressed formats could be used directly
> without any conversion. But the compressed format (with new V4L2_PIX_FMT_
> assigned?) should be preferred (as it provides much higher frame rates). The
> code moved into libv4lconvert would decompress the format and convert into
> something standard (YUV420?).

Correct.

> > Would you perhaps be interested in doing that work?
>
> I can try it. But the hardware isn't mine so my time is limited.

If you could give it a shot that would be great. I've some hardware to
test this with (although I've never actually tested that hardware), so
I can hopefully pick things up if you cannot finish things before you
need to return the hardware.

Thanks & Regards,

Hans
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