Re: [PATCH] drm/i915: [GEN7] Use HW scheduler for fixed function shaders

From: Kenneth Graunke <kenneth@whitecape.org>
To: Ben Widawsky <ben@bwidawsk.net>
Cc: intel-gfx@lists.freedesktop.org,
	Bernard Kilarski <bernard.r.kilarski@intel.com>,
	stable <stable@vger.kernel.org>,
	Ben Widawsky <benjamin.widawsky@intel.com>
Subject: Re: [PATCH] drm/i915: [GEN7] Use HW scheduler for fixed function shaders
Date: Mon, 16 Apr 2012 16:18:50 -0700	[thread overview]
Message-ID: <4F8CA8DA.1000904@whitecape.org> (raw)
In-Reply-To: <1334454092-8878-1-git-send-email-ben@bwidawsk.net>

On 04/14/2012 06:41 PM, Ben Widawsky wrote:
> This originally started as a patch from Bernard as a way of simply
> setting the VS scheduler. After submitting the RFC patch, we decided to
> also modify the DS scheduler. To be most explicit, I've made the patch
> explicitly set all scheduler modes, and included the defines for other
> modes (in case someone feels frisky later).
>
> The rest of the story gets a bit weird. The first version of the patch
> showed an almost unbelievable performance improvement. Since rebasing my
> branch it appears the performance improvement has gone, unfortunately.
> But setting these bits seem to be the right thing to do given that the
> docs describe corruption that can occur with the default settings.
>
> In summary, I am seeing no more perf improvements (or regressions) in my
> limited testing, but we believe this should be set to prevent rendering
> corruption, therefore cc stable.
>
> v1: Clear bit 4 also (Ken + Eugeni)
> Do a full clear + set of the bits we want (Me).
>
> Cc: Bernard Kilarski<bernard.r.kilarski@intel.com>
> Cc: stable<stable@vger.kernel.org>
> Reviewed-by (RFC): Kenneth Graunke<kenneth@whitecape.org>
> Signed-off-by: Ben Widawsky<benjamin.widawsky@intel.com>

Looks good!  I like how you've reworked this.

It looks like we don't want to do this on Haswell.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

(I haven't tested it, though.)