[Mesa-dev] RFC: Fixing FB issues in nv30 gallium

[Ilia Mirkin]

Hello,

I sent a patch earlier to add a new PIPE_CAP about disallowing mixed
fb cbuf/zsbuf sizes, which would be used to disable ARB_fbo. I think
people were generally in favor, but I didn't see any actual
Reviewed-By's, I'll resend it with updated nouveau directories (I
guess everything got moved for some reason) and help text that more
accurately describes the situation.

However, as it turns out, that doesn't go quite far enough. The bpp of
cbuf/zsbuf has to match up as well, which apparently can happen even
without ARB_fbo. Currently st_validate_framebuffer has special logic
to deal with PIPE_CAP_MIXED_COLORBUFFER_FORMATS and return
FRAMEBUFFER_UNSUPPORTED as necessary. I was thinking this could be
handled by adding a pipe_screen->validate_fb() hook, and folding the
MIXED_COLORBUFFER_FORMATS stuff into it (as well as implementing the
nv30-specific logic as well). I could alternatively add another
PIPE_CAP, but I think it's getting to be too much.

Thoughts? Alternate proposals?

Thanks for any feedback,

  -ilia