[Intel-gfx] [PATCH] drm/i915: Make sample_c messages go faster on Haswell.

[Xiang, Haihao]

On Mon, 2014-11-03 at 13:48 +0100, Daniel Vetter wrote:
> 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 ...

Yes, libva driver uses sample (00000) and palette on HSW

Thanks
Haihao


> -Daniel