[Intel-gfx] [PATCH v1 1/2] drm/i915:skl: Add WaEnableGapsTsvCreditFix

[Mika Kuoppala]

Ben Widawsky <benjamin.widawsky at intel.com> writes:

> On Mon, Aug 03, 2015 at 08:24:56PM +0100, Arun Siluvery wrote:
>> Cc: Ben Widawsky <benjamin.widawsky at intel.com>
>> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
>> Signed-off-by: Arun Siluvery <arun.siluvery at linux.intel.com>
>> ---
>>  drivers/gpu/drm/i915/i915_reg.h | 3 +++
>>  drivers/gpu/drm/i915/intel_pm.c | 6 ++++++
>>  2 files changed, 9 insertions(+)
>> 
>> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
>> index 77967ca..8991cd5 100644
>> --- a/drivers/gpu/drm/i915/i915_reg.h
>> +++ b/drivers/gpu/drm/i915/i915_reg.h
>> @@ -6849,6 +6849,9 @@ enum skl_disp_power_wells {
>>  #define GEN7_MISCCPCTL			(0x9424)
>>  #define   GEN7_DOP_CLOCK_GATE_ENABLE	(1<<0)
>>  
>> +#define GEN8_GARBCNTL                   0xB004
>> +#define   GEN9_GAPS_TSV_CREDIT_DISABLE  (1<<7)
>> +
>>  /* IVYBRIDGE DPF */
>>  #define GEN7_L3CDERRST1			0xB008 /* L3CD Error Status 1 */
>>  #define HSW_L3CDERRST11			0xB208 /* L3CD Error Status register 1 slice 1 */
>> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
>> index c23cab6..9152113 100644
>> --- a/drivers/gpu/drm/i915/intel_pm.c
>> +++ b/drivers/gpu/drm/i915/intel_pm.c
>> @@ -106,6 +106,12 @@ static void skl_init_clock_gating(struct drm_device *dev)
>>  		/* WaDisableLSQCROPERFforOCL:skl */
>>  		I915_WRITE(GEN8_L3SQCREG4, I915_READ(GEN8_L3SQCREG4) |
>>  			   GEN8_LQSC_RO_PERF_DIS);
>> +
>> +	/* WaEnableGapsTsvCreditFix:skl */
>> +	if (IS_SKYLAKE(dev) && (INTEL_REVID(dev) >= SKL_REVID_C0)) {
>> +		I915_WRITE(GEN8_GARBCNTL, (I915_READ(GEN8_GARBCNTL) |
>> +					   GEN9_GAPS_TSV_CREDIT_DISABLE));
>> +	}
>>  }
>>  
>>  static void bxt_init_clock_gating(struct drm_device *dev)
>
> FWIW, the docs make it sound like BIOS should be doing this. Did you verify we
> actually don't have the bit set with more recent BKC?
>

I have pretty recent BIOS and the bit was not set.

> Tested-by: Ben Widawsky <ben at bwidawsk.net>
> Reviewed-by: Ben Widawsky <ben at bwidawsk.net>
>

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90854
Tested-by: Mika Kuoppala <mika.kuoppala at intel.com>

> -- 
> Ben Widawsky, Intel Open Source Technology Center
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