[Intel-gfx] [PATCH] drm/i915: add render standby support
jbarnes at virtuousgeek.org
Thu Oct 8 19:04:30 CEST 2009
On Thu, 8 Oct 2009 12:55:00 -0400
Andrew Lutomirski <luto at mit.edu> wrote:
> On Thu, Oct 8, 2009 at 12:46 PM, Jesse Barnes
> <jbarnes at virtuousgeek.org> wrote:
> > On Thu, 8 Oct 2009 12:04:32 +0200
> > Erik Andrén <erik.andren at gmail.com> wrote:
> >> 2009/10/7 Jesse Barnes <jbarnes at virtuousgeek.org>:
> >> > Render standy allows the GPU to power down the render unit when
> >> > idle. In order for this to work, it needs a page of graphics
> >> > memory to save state. This patch allocates that page and
> >> > enables the feature on supported chipsets.
> >> >
> >> > Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
> >> > ---
> >> Do you have any figures on how much power this saves?
> > I haven't done any measurements yet. I had to do this as part of
> > some other work and figured I'd get it out there after some light
> > testing.
> For fun, I compiled and ran it on my laptop. I didn't get any
> noticeable savings over 2.6.32-rc3 (with a hack added in to
> force-enable render_reclock_avail and lvds_downclock_avail on my
> GM45), but nothing went wrong either.
> While I'm here, silly question: what's supposed to enable
Not silly at all. :) That code can't be enabled until we figure out a
reliable way of getting secondary (reduced) refresh timings for the
builtin panel. We have some info on it but haven't tested it against a
wide variety of VBIOSes yet.
Jesse Barnes, Intel Open Source Technology Center
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