Re: [PATCH 0/6] drm/i915: Remaining PSR fixes

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, May 31, 2016 at 09:07:49PM +0200, Daniel Vetter wrote:
> On Tue, May 31, 2016 at 06:50:24PM +0300, ville.syrjala@linux.intel.com wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > 
> > Here's a repost of my PSR fixes, and one straggler from Daniel.
> > 
> > One interesting thing I noticed is that my SKL actually hits the PSR setup
> > time vs. vblank length check, so after these patches that machine won't
> > actually use PSR. The panel does support a lower refresh rate timing as well
> > though which doesn't suffer from this limitation, so I hacked the code to
> > use that mode instead, and PSR did seem to work without problems. With the
> > original mode I had some screen stalls while running xonotic, which I'm
> > going to assume were due to the setup time exceeding the safe limit.
> 
> Hm, is there a way to make that hack less hackish and merge it? Selecting
> a mode with slightly different timings (but same resolution ofc) to make
> PSR possible seems like a very sensible idea. Or is this a 60Hz vs 30Hz
> kind of thing?

60 vs. 48 in this case, so might not want it as a default. However
this is not a production machine anyway, so I wouldn't worry about
it too much unless someone comes across a real machine with a
similar setup.

> 
> Scrolled through patches, still lgtm.
> -Daniel
> 
> > 
> > I also hooked up the PSR interrupts for BDW+ and pushed the patches to [1],
> > but I'm not including those patches here since the PSR interrupts don't
> > seem to gain us anything useful in practice.
> > 
> > [1] git://github.com/vsyrjala/linux.git psr_interrupts
> > 
> > Daniel Vetter (1):
> >   drm/i915/psr: Skip aux handeshake if the vbt tells us to
> > 
> > Ville Syrjälä (5):
> >   drm/dp: Add drm_dp_psr_setup_time()
> >   drm/dp: Add drm_dp_psr_need_train_on_exit()
> >   drm/i915: Check PSR setup time vs. vblank length
> >   drm/i915: Ask the sink whether training is required when exiting PSR
> >     main-link off mode
> >   drm/i915: Move psr.link_standby setup to intel_psr_match_conditions()
> > 
> >  drivers/gpu/drm/drm_dp_helper.c     | 46 ++++++++++++++++++++++++++
> >  drivers/gpu/drm/i915/intel_drv.h    |  2 ++
> >  drivers/gpu/drm/i915/intel_psr.c    | 64 +++++++++++++++++++++++++------------
> >  drivers/gpu/drm/i915/intel_sprite.c |  6 ++--
> >  include/drm/drm_dp_helper.h         |  3 ++
> >  5 files changed, 97 insertions(+), 24 deletions(-)
> > 
> > -- 
> > 2.7.4
> > 
> > _______________________________________________
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> > dri-devel@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

-- 
Ville Syrjälä
Intel OTC
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