Re: [PATCH 1/2] drm/i915/chv: Add few more CHV workarounds

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

On Tue, Oct 28, 2014 at 01:32:01PM +0000, Siluvery, Arun wrote:
> On 28/10/2014 12:23, Ville Syrjälä wrote:
> > On Tue, Oct 28, 2014 at 11:57:50AM +0000, Arun Siluvery wrote:
> >> WaDisableInstructionShootdown:chv
> >> WaForceEnableNonCoherent:chv
> >> WaHdcDisableFetchWhenMasked:chv
> >> WaDisableFenceDestinationToSLM:chv (pre-production)
> >>
> >> s/WaDisableDopClockGating/WaDisableRowChickenDopClockGating, because another
> >> CHV WA is defined with the same name in intel_pm.c for a different reg.
> >>
> >> For: VIZ-4090
> >> Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
> >> ---
> >>   drivers/gpu/drm/i915/i915_reg.h         |  2 ++
> >>   drivers/gpu/drm/i915/intel_ringbuffer.c | 20 ++++++++++++++++++--
> >>   2 files changed, 20 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> >> index 77fce96..840e5d9 100644
> >> --- a/drivers/gpu/drm/i915/i915_reg.h
> >> +++ b/drivers/gpu/drm/i915/i915_reg.h
> >> @@ -5024,6 +5024,7 @@ enum punit_power_well {
> >>   /* GEN8 chicken */
> >>   #define HDC_CHICKEN0				0x7300
> >>   #define  HDC_FORCE_NON_COHERENT			(1<<4)
> >> +#define  HDC_DONOT_FETCH_MEM_WHEN_MASKED	(1<<11)
> >>   #define  HDC_FENCE_DEST_SLM_DISABLE		(1<<14)
> >>
> >>   /* WaCatErrorRejectionIssue */
> >> @@ -5941,6 +5942,7 @@ enum punit_power_well {
> >>   #define   GEN9_DG_MIRROR_FIX_ENABLE	(1<<5)
> >>
> >>   #define GEN8_ROW_CHICKEN		0xe4f0
> >> +#define   INSTRUCTION_SHOOTDOWN_DISABLE (1<<9)
> >>   #define   PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE	(1<<8)
> >>   #define   STALL_DOP_GATING_DISABLE		(1<<5)
> >>
> >> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> >> index a8f72e8..2c07a02 100644
> >> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> >> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> >> @@ -788,14 +788,30 @@ static int chv_init_workarounds(struct intel_engine_cs *ring)
> >>   	struct drm_i915_private *dev_priv = dev->dev_private;
> >>
> >>   	/* WaDisablePartialInstShootdown:chv */
> >> +	/* WaDisableInstructionShootdown:chv */
> >>   	WA_SET_BIT_MASKED(GEN8_ROW_CHICKEN,
> >> -		  PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE);
> >> +			  PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE |
> >> +			  (dev->pdev->revision < 0x06 ?
> >> +			   INSTRUCTION_SHOOTDOWN_DISABLE : 0));
> >
> > I think we should just drop the current early pre-prod workarounds, and
> > not add more of them.
> >
> ok I will drop this.
> Is there any guideline on particular revision for bdw, chv below which 
> we should drop that workaround?

The usual rule is to drop all pre-prod w/as once we know what actually
is the first production stepping. But obviosuly it's still a bit too
early to do that on chv. At this time I would just drop all A step ones.

> 
> >>
> >>   	/* WaDisableThreadStallDopClockGating:chv */
> >>   	WA_SET_BIT_MASKED(GEN8_ROW_CHICKEN,
> >>   		  STALL_DOP_GATING_DISABLE);
> >>
> >> -	/* WaDisableDopClockGating:chv (pre-production hw) */
> >> +	/* Use Force Non-Coherent whenever executing a 3D context. This is a
> >> +	 * workaround for a possible hang in the unlikely event a TLB
> >> +	 * invalidation occurs during a PSD flush.
> >> +	 */
> >
> > We haven't generally documented the w/as in any great detail. Does it
> > help someone if we start doing that?
> 
> This was already documented for bdw hence I included it for chv also.

OK. Being a bit more consistent between bdw and chv shouldn't hurt.

> 
> regards
> Arun
> 
> >
> >> +	/* WaForceEnableNonCoherent:chv */
> >> +	/* WaHdcDisableFetchWhenMasked:chv */
> >> +	/* WaDisableFenceDestinationToSLM:chv (pre-production) */
> >> +	WA_SET_BIT_MASKED(HDC_CHICKEN0,
> >> +			  HDC_FORCE_NON_COHERENT |
> >> +			  HDC_DONOT_FETCH_MEM_WHEN_MASKED |
> >> +			  (dev->pdev->revision < 0x06 ?
> >> +			   HDC_FENCE_DEST_SLM_DISABLE : 0));
> >> +
> >> +	/* WaDisableRowChickenDopClockGating:chv (pre-production hw) */
> >>   	WA_SET_BIT_MASKED(GEN7_ROW_CHICKEN2,
> >>   		  DOP_CLOCK_GATING_DISABLE);
> >>
> >> --
> >> 2.1.2
> >>
> >> _______________________________________________
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> >> Intel-gfx@lists.freedesktop.org
> >> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >

-- 
Ville Syrjälä
Intel OTC
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