[Mesa-stable] [Mesa-dev] [PATCH 2/2] mesa: _mesa_format_convert should be endian agnostic

[Oded Gabbay]

On Mon, Aug 3, 2015 at 6:40 PM, Emil Velikov <emil.l.velikov at gmail.com>
wrote:

> Hi Oded,
>
> On 2 August 2015 at 11:37, Oded Gabbay <oded.gabbay at gmail.com> wrote:
> > This patch fixes a bug that is manifested in the read path of mesa when
> > running on big-endian machines. The effects can be seen when running
> > piglit sanity test and/or taking a screen capture.
> >
> > The bug is caused when _mesa_format_convert receives src_format as
> > mesa_format, which it thens changes to mesa_array_format. During this
> > change, it checks for endianness and swaps the bytes accordingly.
> > However, because the bytes are _already_ swapped in the memory itself
> > (being written there by llvmpipe), and src_format value matches the
> > _actual_ contents of the memory, the result of the read is wrong.
> >
> I'm assuming that you're looked at swrast + softpipe as well - do they
> use the same approach or is llvmpipe the odd one out ?
>
> ​Hi Emil,
​

​I checked it with swrast, softpipe AND llvmpipe.
Without my patch, all methods fail piglit sanity on ppc64
With my patch, all ​methods pass piglit sanity

   Oded



> Curious if your work has any effect on the big endian + r600 issue
> [1]. I believe Christian Zigotzky (Cc'ed) was very passionate about
> getting his r600 working - perhaps he can give your patches a test ?
> ... just to make sure that things don't go even worse :)
>
>
> Cheers,
> Emil
>
> [1] https://bugs.freedesktop.org/show_bug.cgi?id=72877
>
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