[Intel-gfx] [PATCH] drm/i915: Display WA #1185 WaDisableDARBFClkGating:cnl, glk

[Rodrigo Vivi]

On Thu, Nov 09, 2017 at 01:45:04PM +0000, Ville Syrjälä wrote:
> On Wed, Nov 08, 2017 at 03:30:16PM -0800, Rodrigo Vivi wrote:
> > PM Rsp is not sent when plane is turned off at around the
> > time that a PM fill Req is received by display
> 
> Do we know what the impact of this is? The HSD just seems to say
> "Detection method: Hang" which isn't partciluarly helpful.
> 
> To me this smells vaguely of WaRsPkgCStateDisplayPMReq:hsw which
> will cause a system hang if we don't do it early enough. Do we have
> similar concerns here?

Well, I do have a bad display hang here and this patch didn't help...

> (and if so please look at commit f72b84c677d6
> ("drm/i915: Move init_clock_gating() back to where it was"))

oh cool! thanks I will take a look on this...

> 
> Maybe we should start a new init_clock_gating/init_workarounds thing
> just for the display, and add all new stuff there? And then we can
> start moving the old display w/as etc. there as well.

Maybe this is a work for that series that Oscar is working on?

Thanks,
Rodrigo.

> 
> > 
> > WA: disable arbiter clock gating, set bit [27] of 0x46530
> > 
> > Cc: Radhakrishna Sripada <radhakrishna.sripada at intel.com>
> > Cc: Imre Deak <imre.deak at intel.com>
> > Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_reg.h | 1 +
> >  drivers/gpu/drm/i915/intel_pm.c | 8 ++++++++
> >  2 files changed, 9 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > index 6ef33422f762..fc8c5f8260f6 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -3819,6 +3819,7 @@ enum {
> >   * GEN9 clock gating regs
> >   */
> >  #define GEN9_CLKGATE_DIS_0		_MMIO(0x46530)
> > +#define   DARBF_GATING_DIS		(1 << 27)
> >  #define   PWM2_GATING_DIS		(1 << 14)
> >  #define   PWM1_GATING_DIS		(1 << 13)
> >  
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index e09377df590d..e642e8983035 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -127,6 +127,10 @@ static void glk_init_clock_gating(struct drm_i915_private *dev_priv)
> >  	u32 val;
> >  	gen9_init_clock_gating(dev_priv);
> >  
> > +	/* Display WA #1185 WaDisableDARBFClkGating:glk */
> > +	I915_WRITE(GEN9_CLKGATE_DIS_0, I915_READ(GEN9_CLKGATE_DIS_0) |
> > +		   DARBF_GATING_DIS);
> > +
> >  	/*
> >  	 * WaDisablePWMClockGating:glk
> >  	 * Backlight PWM may stop in the asserted state, causing backlight
> > @@ -8528,6 +8532,10 @@ static void cnl_init_clock_gating(struct drm_i915_private *dev_priv)
> >  	u32 val;
> >  	cnp_init_clock_gating(dev_priv);
> >  
> > +	/* Display WA #1185 WaDisableDARBFClkGating:cnl */
> > +	I915_WRITE(GEN9_CLKGATE_DIS_0, I915_READ(GEN9_CLKGATE_DIS_0) |
> > +		   DARBF_GATING_DIS);
> > +
> >  	/* This is not an Wa. Enable for better image quality */
> >  	I915_WRITE(_3D_CHICKEN3,
> >  		   _MASKED_BIT_ENABLE(_3D_CHICKEN3_AA_LINE_QUALITY_FIX_ENABLE));
> > -- 
> > 2.13.6
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Ville Syrjälä
> Intel OTC