Re: [PATCH] drm/i915: Make sample_c messages go faster on Haswell.

Daniel Vetter
2014-11-03T12:48:00Z

On Fri, Oct 31, 2014 at 11:27:33AM +0200, Ville Syrjälä wrote:
> On Thu, Oct 30, 2014 at 12:57:04PM -0700, Kenneth Graunke wrote:
> > Before we get too much further...we should check if libva is actually broken.
> > I don't know if this means the sampler palette completely doesn't work, or if
> > it just means sample_c doesn't work with the palette. If it's the latter,
> > we're probably fine, because I doubt libva uses sample_c.
>
> Yeah if we wouldn't break any existing userspace I guess we could just
> flip the switch in the kernel. If anyone later wants to start doing
> something that no longer works they'd have to deal with disabling the
> bit using an LRI.

It very much looks like libva uses palettes, since it supports C8 and C4
image formats (well some crazy fourcc nonsense, but meh). And it does so
on all generations support by the libva driver, i.e. including hsw afaict

Cc'ing people and lists with more clue who should be able to tell whether
its not just there but actually works ...
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch