[Intel-gfx] [PATCH 2/7] drm/i915: Fix non-scaled sprites for ILK

[Ville Syrjälä]

On Thu, Oct 17, 2013 at 09:56:03PM +0100, Chris Wilson wrote:
> On Thu, Oct 17, 2013 at 10:53:14PM +0300, ville.syrjala at linux.intel.com wrote:
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > 
> > For some reason we're enabling sprite scaling on ILK always. That
> > doesn't work well with the new watermark code that expects to use
> > LP1 watermarks with unscaled sprites.
> > 
> > Only enable sprite scaling on ILK when actually needed, just like
> > we do on SNB.
> 
> The sprite plane simply didn't work on my ilk machine unless I
> enabled the scaler. If you want to revert it, at least mention which
> patch you are reverting with justification/demonstration that it works
> now.

Hmm. Oh I see it actually does work when the scaler is enabled. I'm
going to assume the hardware automagically disables LP1+ watermarks in
that case or something, and then it just happens to work even though we
don't set up the watermarks correctly. Earlier I was trying with a >1k
wide 32bpp source w/o scaling, so it exceeded the scaler limits
(width_bytes > 4096) but since the code that does the check didn't
realize scaling was actually enabled it let it through and the
hardware didn't like that very much.

So since it kind of works currently with smaller source widths, I'm
going to leave it alone until I send out the watermark changes. And
I'll pimp up the commit message at that point.

-- 
Ville Syrjälä
Intel OTC