Re: [PATCH] drm/i915/chv: Implement WaDisableShadowRegForCpd

[Deepak S <deepak.s@linux.intel.com>]

On Tuesday 14 April 2015 04:29 PM, Ville Syrjälä wrote:
> On Tue, Apr 14, 2015 at 03:58:54PM +0530, deepak.s@linux.intel.com wrote:
>> From: Deepak S <deepak.s@linux.intel.com>
>>
>> This WA disable usage of shadow register during CPD/RC6 transactions on
>> CHV
> I suppose is a workaround for the shadow vs. wake FIFO problem... Yeah
> hsd seems to agree (after a bit of extra digging).

Yes ville, this WA is avoid problem between shadow vs wake FIFO unload problem.
I will address the comments and send new patch set

>> Signed-off-by: Deepak S <deepak.s@linux.intel.com>
>> ---
>>   drivers/gpu/drm/i915/i915_reg.h | 1 +
>>   drivers/gpu/drm/i915/intel_pm.c | 4 ++++
>>   2 files changed, 5 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
>> index 9c97842..bcdb16b 100644
>> --- a/drivers/gpu/drm/i915/i915_reg.h
>> +++ b/drivers/gpu/drm/i915/i915_reg.h
>> @@ -6206,6 +6206,7 @@ enum skl_disp_power_wells {
>>   #define  GTFIFOCTL				0x120008
>>   #define    GT_FIFO_FREE_ENTRIES_MASK		0x7f
>>   #define    GT_FIFO_NUM_RESERVED_ENTRIES		20
>> +#define GT_FIFO_CTL_BLOCK_POLICY	(3<<11)
> GT_FIFO_CTL_BLOCK_ALL_POLICY_STALL	(1 << 12)
> GT_FIFO_CTL_RC6_POLICY_STALL		(1 << 11)
>
> perhaps?

>>   
>>   #define  HSW_IDICR				0x9008
>>   #define    IDIHASHMSK(x)			(((x) & 0x3f) << 16)
>> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
>> index 4dd8b41..b9d3c00 100644
>> --- a/drivers/gpu/drm/i915/intel_pm.c
>> +++ b/drivers/gpu/drm/i915/intel_pm.c
>> @@ -6431,6 +6431,10 @@ static void cherryview_init_clock_gating(struct drm_device *dev)
>>   	/* WaDisableSDEUnitClockGating:chv */
>>   	I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) |
>>   		   GEN8_SDEUNIT_CLOCK_GATE_DISABLE);
>> +
>> +	/* WaDisableShadowRegForCpd */
>> +	I915_WRITE(GTFIFOCTL, I915_READ(GTFIFOCTL) |
>> +						  GT_FIFO_CTL_BLOCK_POLICY);
> I think __intel_uncore_early_sanitize() might be a better place for
> this.
>
>>   }
>>   
>>   static void g4x_init_clock_gating(struct drm_device *dev)
>> -- 
>> 1.9.1

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