[Intel-gfx] [PATCH v2] drm/i915: enable memory self refresh on 945

[Eric Anholt]

On Thu, 10 Dec 2009 11:52:01 -0800, Jesse Barnes <jbarnes at virtuousgeek.org> wrote:
> On Wed, 09 Dec 2009 13:25:39 +0800
> Li Peng <peng.li at linux.intel.com> wrote:
> 
> > I did some test and found that memory self refresh on 945
> > isn't really enabled in commit 652c39. On 945, we need to use
> > bit 31 of FW_BLC_SELF to enable the write to self refresh bit
> > and bit 16 to enable the write of self refresh watermark, and
> > memory self refresh will take effect when CPU enters C3+ state.
> > 
> > This patch enables memory self refresh on 945 when graphics
> > is idle, and disable self refresh when it is busy. In my test
> > on a netbook of 945GSE chipset, it saves about 0.8W idle power.
> > 
> > Signed-off-by: Li Peng <peng.li at intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_reg.h      |    4 +++-
> >  drivers/gpu/drm/i915/intel_display.c |   23 ++++++++++++++++++++++-
> >  2 files changed, 25 insertions(+), 2 deletions(-)
> 
> I'd like to figure out why I don't see hangs on my AspireOne without
> the idle/busy change you have here, since SR should be totally
> automatic afaik. Also, we may as well include the i915 path as well
> (after testing some more of course), since it affects this same code
> path.

Where are we at on this one?
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