[Intel-gfx] [PATCH] drm/i915:: Disable FBC on SandyBridge

[Daniel Vetter]

On Tue, Jan 17, 2012 at 12:16, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Tue, 17 Jan 2012 11:57:05 +0100, Daniel Vetter <daniel at ffwll.ch> wrote:
>> On Tue, Nov 08, 2011 at 11:17:34PM +0000, Chris Wilson wrote:
>> > Enabling FBC is causing the BLT ring to run between 10-100x slower than
>> > normal and frequently lockup. The interim solution is disable FBC once
>> > more until we know why.
>> >
>> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>>
>> Iirc fbc isn't really worth it power-wise on snb and we don't implement it on
>> ivb. So shouldn't we just disable it completely? Eugeni, any opinions - I
>> think you're most up to speed on power saving figures for snb?
>
> Also note that I've had a couple of people confirm this bug and tested
> the patch on IRC. Doesn't help explain precisely what is wrong nor if
> there is a better workaround amidst the chicken bits that we've missed.

Keith, I think the disable-fbc-on-snb should go to -fixes. Eugeni can
meanwhile figure out whether it's worth it on ivb or not and what we
should do with this mess in -next. Hence this patch is (for -fixes)
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
-Daniel
-- 
Daniel Vetter
daniel.vetter at ffwll.ch - +41 (0) 79 364 57 48 - http://blog.ffwll.ch