GFXv8/Polaris on big endian

[Marcus Comstedt]

Hi Michel,

Thanks for your reply.


Michel Dänzer <michel at daenzer.net> writes:

> Not sure what kind of compatibility you mean.

I was referring to the gfx_v6 driver, which I believed was already BE
compatiple (although this may have been a misunderstanding), using a
different mechanism, which would then clash with the "byteswap in
amdgpu_ring_write" method, since the amdgpu_ring_write function
is shared and not virtualized via the ring ops.


> Anyway, AFAIK all GPUs supported by amdgpu simply don't have these byte
> swapping capabilities anymore. This will pose a much bigger challenge in
> the shader related code in Mesa.

I find it strange that they would still have the bits in the registers
then.  In v8 they were even moved to a different bit offset; if they
were not supported why were they not simply removed?

But if the capability is definitely not there, then I guess I'll go for
the software swapping route.  I'll consider it a success if I get
/dev/fb, Mesa is an adventure for a different day.  :-)


> My advice would be to reconsider whether whatever reasons you have for
> running in big endian mode are worth the pain. :)

I'm reconsidering if RX 550 is really worth the trouble when I could
just use an R7 which has a known working driver (including 3D), but it
also feels like a bit of a cop out to give up after having good progress
so far...


  // Marcus


-- 
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Marcus Comstedt                          Lysator Academic Computer Society
marcus at lysator.liu.se                    Linköping University, Sweden   //
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