[Intel-gfx] [PATCH 1/2] drm/i915: Re-add enable_rc6 modparam

[Rodrigo Vivi]

On Fri, May 17, 2019 at 07:34:23PM +0300, Ville Syrjälä wrote:
> On Fri, May 17, 2019 at 09:17:39AM -0700, Rodrigo Vivi wrote:
> > On Thu, May 16, 2019 at 03:49:19PM +0000, Summers, Stuart wrote:
> > > On Thu, 2019-05-16 at 18:42 +0300, Jani Nikula wrote:
> > > > On Thu, 16 May 2019, "Summers, Stuart" <stuart.summers at intel.com>
> > > > wrote:
> > > > > On Thu, 2019-05-16 at 12:59 +0300, Jani Nikula wrote:
> > > > > > On Tue, 14 May 2019, Rodrigo Vivi <rodrigo.vivi at intel.com> wrote:
> > > > > > > One possibility that just came to my mind now is, what if we
> > > > > > > make
> > > > > > > this only for platforms that are still protected by
> > > > > > > is_alpha_support=1
> > > > > > > (soon becoming require_force_probe=1)
> > > > > > 
> > > > > > Please don't conflate alpha_support or force_probe with
> > > > > > *anything*
> > > > > > else.
> > > > > > 
> > > > > > > But this is just one side of the coin... when product is out
> > > > > > > there
> > > > > > > and we want the user to debug the issue to see if it is a RC6
> > > > > > > bug
> > > > > > > we have no way to verify that. :/
> > > > > > 
> > > > > > The problem is, if it works with rc6 disabled, it doesn't prove
> > > > > > it's
> > > > > > an
> > > > > > rc6 bug either.
> > 
> > Well, RC6 is the main GT power gating. The issue could be on may other
> > individual power gating, but if by disabling RC6 the issue is gone
> > it is a very good indication that it is a GT-PM bug somewhere.
> 
> I disagree. In the recent past enable_rc6 was often used by
> people to workaround display underruns and whatnot.

o.O
do you mean this was being used as a placebo? or real issue?
or something like by keeping rc6 gpu was keeping the power request
to punit high so display was receiving enough power to not strugle
with wm? or something like that or what?

> 
> -- 
> Ville Syrjälä
> Intel
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