[Intel-gfx] [PATCH 15/53] drm/i915/bdw: Don't write PDP in the legacy way when using LRCs

[Mateo Lozano, Oscar]

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> -----Original Message-----
> From: Volkin, Bradley D
> Sent: Thursday, June 19, 2014 12:43 AM
> To: Mateo Lozano, Oscar
> Cc: intel-gfx at lists.freedesktop.org
> Subject: Re: [Intel-gfx] [PATCH 15/53] drm/i915/bdw: Don't write PDP in the
> legacy way when using LRCs
> 
> On Fri, Jun 13, 2014 at 08:37:33AM -0700, oscar.mateo at intel.com wrote:
> > From: Oscar Mateo <oscar.mateo at intel.com>
> >
> > This is mostly for correctness so that we know we are running the LR
> > context correctly (this is, the PDPs are contained inside the context
> > object).
> >
> > v2: Move the check to inside the enable PPGTT function. The switch
> > happens in two places: the legacy context switch (that we won't hit
> > when Execlists are enabled) and the PPGTT enable, which unfortunately
> > we need. This would look much nicer if the ppgtt->enable was part of
> > the ring init, where it logically belongs.
> >
> > Signed-off-by: Oscar Mateo <oscar.mateo at intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_gem_gtt.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > index 8b3cde7..9f0c69e 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > @@ -844,6 +844,11 @@ static int gen8_ppgtt_enable(struct
> i915_hw_ppgtt *ppgtt)
> >  		if (USES_FULL_PPGTT(dev))
> >  			continue;
> >
> > +		/* In the case of Execlists, we don't want to write the PDPs
> > +		 * in the legacy way (they live inside the context now) */
> > +		if (intel_enable_execlists(dev))
> > +			return 0;
> 
> Along the lines of one of Daniel's comments about the module parameter, I
> think we could use some clarity on when to use intel_enable_execlists() vs
> lrc_enabled vs i915.enable_execlists.

Yep. I´ll look at this in v4. It´s probably better doing the early sanitize as Daniel suggested and then just use i915.enable_execlists everywhere.

-- Oscar