[Mesa-dev] Wrong colors in 3D apps on big-endian systems

[Christian Zigotzky]

Am 11.03.14 16:25, schrieb Richard Sandiford:
> Christian Zigotzky <chzigotzky at xenosoft.de> writes:
>> Am 11.03.14 12:08, schrieb Richard Sandiford:
>>> Michel Dänzer <michel at daenzer.net> writes:
>>>> On Mon, 2014-03-10 at 10:11 +0100, Christian Zigotzky wrote:
>>>>> On 10.03.2014 02:49, Michel Dänzer wrote:
>>>>>> Congratulations, you just broke llvmpipe again on big endian systems. ;)
>>>>> I'm sorry but Mesa classic works very well on Debian Sid and Lubuntu
>>>>> 14.04 with these changes. ;) Why does Mesa classic work with the
>>>>> little-endian defines?
>>>> What do you mean by 'Mesa classic'? The r600g driver works with the
>>>> little endian defines because r600g assumes st/mesa uses the formats the
>>>> way it did before the llvmpipe big endian fixes.
>>>>
>>>>>> Did you even look at the commits introducing those defines? Did you
>>>>>> really think those defines, with explicit endianness checks, were
>>>>>> introduced for no reason but to break drivers on big endian systems?
>>>>>>
>>>>>>
>>>>>> I explained the problem in r600g and how it could be solved. Please
>>>>>> explore that.
>>>>> I'll try to explore that but I don't have any knowledge about the Mesa
>>>>> source code. The Fedora guys have solved the problem with the patch
>>>>> "mesa-9.2-llvmpipe-on-big-endian.patch". What do you think of this patch?
>>>> It sounds like an older downstream attempt at fixing llvmpipe on big
>>>> endian hosts, which was superseded by the upstream fixes, which were
>>>> incidentally pushed by the 'Fedora guy' Adam Jackson. Adding him and
>>>> Richard Sandiford (the author of the fixes) to CC, maybe they can help
>>>> you fix up r600g.
>>> I don't know the r600 code at all, sorry.  But like you say, if the code
>>> is treating the x8y8z8w8 formats as low-to-high integers (x in lsb, z in msb)
>>> then the right fix should be to use PIPE_FORMAT_xyzw8888_* instead of
>>> PIPE_FORMAT_x8y8z8w8_*.
>>>
>>> Thanks,
>>> Richard
>>>
>>>
>> Richard,
>>
>> How can I change the formats x8y8z8w8 to xyzw8888?
> I just mean changing instances of things like PIPE_FORMAT_A8R8G8B8_UNORM
> to PIPE_FORMAT_ARGB8888_UNORM in the relevant parts of the r600 support
> (which is I think what Michel also meant -- like I say, I'm not really
> adding anything new here).  PIPE_FORMAT_ARGB8888_UNORM always has the
> alpha channel in the low bits of a 32-bit int according to host endianness,
> whereas PIPE_FORMAT_A8R8G8B8_UNORM always has the alpha channel in the
> first byte of memory.
>
> I can't say for sure which the "revelavant parts" are because I don't
> know the r600 code.
>
> Thanks,
> Richard
>
>
Thanks a lot for your answer. I've found PIPE_FORMAT_A8R8G8B8_UNORM in 
the files r600_state.c and evergreen_state.c. I'm going to change these 
to PIPE_FORMAT_ARGB8888_UNORM.

--Christian