Re: [PATCH] drm/i915/bdw: Use timeout mode for RC6 on bdw

[Ben Widawsky <ben@bwidawsk.net>]

On Wed, Apr 30, 2014 at 02:14:02PM -0700, Kristen Carlson Accardi wrote:
> On Thu, 01 May 2014 00:03:15 +0300
> Imre Deak <imre.deak@intel.com> wrote:
> 
> > On Wed, 2014-04-30 at 13:41 -0700, Ben Widawsky wrote:
> > > On Wed, Apr 30, 2014 at 01:34:36PM -0700, Kristen Carlson Accardi wrote:
> > > > On Tue, 29 Apr 2014 22:31:49 -0700
> > > > Ben Widawsky <ben@bwidawsk.net> wrote:
> > > > 
> > > > > On Wed, Apr 09, 2014 at 11:44:06AM -0700, Tom O'Rourke wrote:
> > > > > > Higher RC6 residency is observed using timeout mode
> > > > > > instead of EI mode.  This applies to Broadwell only.
> > > > > > The difference is particularly noticeable with video
> > > > > > playback.
> > > > > > 
> > > > > > Issue: VIZ-3778
> > > > > > Change-Id: I62bb12e21caf19651034826b45cde7f73a80938d
> > > > > > Signed-off-by: Tom O'Rourke <Tom.O'Rourke@intel.com>
> > > > > 
> > > > > I've merged this one to my bdw-rc6 branch, and therefore my broadwell
> > > > > branch. Hopefully Kristen will see some improvement.
> > > > 
> > > > Unfortunately, I built your bdw-rc6 branch along with the revert
> > > > I need to get my panel to work, and I get zero rc6 residency.  Do I
> > > > have to explicitly enable it?
> > > 
> > > I'm not actually sure. You can try it and let me know. I haven't had any
> > > time to verify the rebase. We can check my hack.
> > 
> > Note that in -nightly you also have to update sanitize_rc6_option()
> > along with intel_enable_gt_powersave() and intel_disable_gt_powersave()
> > since atm these keep RC6 disabled on BDW.
> > 
> > --Imre
> > 
> 
> 
> Yes, I reverted fb5ed3b201fe5670c9ffeec3b5f6ff044d543c9e and was able
> to see some rc6 residency.  With the idle workload, residency appears
> to be similar to before, so no regression.

Thanks. I'll squash this in where appropriate.

-- 
Ben Widawsky, Intel Open Source Technology Center