[Intel-gfx] [PATCH 09/23] drm/i915/edp: Add WaKVMNotificationOnConfigChange:bdw, skl

[Mika Kuoppala]

Mika Kuoppala <mika.kuoppala at linux.intel.com> writes:

> [ text/plain ]
> According to bspec this workaround helps to reduce lag and improve
> performance on edp.
>

Bspec says this is for bdw,skl.
wa database says this is for bdw and all gen9.

If we write to 0x42090 on kbl,skl it doesn't
hold value and we get the mmio debug traces as
shown in the CI/bat.

Lets make this for bdw only as it seems to
have this register.

-Mika



> References: HSD#2134579
> Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_reg.h | 3 +++
>  drivers/gpu/drm/i915/intel_pm.c | 8 ++++++++
>  2 files changed, 11 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index e3077259541a..1f84c2ff3563 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6035,6 +6035,9 @@ enum skl_disp_power_wells {
>  #define  FORCE_ARB_IDLE_PLANES	(1 << 14)
>  #define  SKL_EDP_PSR_FIX_RDWRAP	(1 << 3)
>  
> +#define CHICKEN_PAR2_1		_MMIO(0x42090)
> +#define  KVM_CONFIG_CHANGE_NOTIFICATION_SELECT	(1 << 14)
> +
>  #define _CHICKEN_PIPESL_1_A	0x420b0
>  #define _CHICKEN_PIPESL_1_B	0x420b4
>  #define  HSW_FBCQ_DIS			(1 << 22)
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index fc34add6ab82..5d9b7ff9dc18 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -6870,6 +6870,10 @@ static void skylake_init_clock_gating(struct drm_device *dev)
>  	/* See Bspec note for PSR2_CTL bit 31, Wa#828:skl */
>  	I915_WRITE(CHICKEN_PAR1_1,
>  		   I915_READ(CHICKEN_PAR1_1) | SKL_EDP_PSR_FIX_RDWRAP);
> +
> +	/* WaKVMNotificationOnConfigChange:skl */
> +	I915_WRITE(CHICKEN_PAR2_1, I915_READ(CHICKEN_PAR2_1)
> +		   | KVM_CONFIG_CHANGE_NOTIFICATION_SELECT);
>  }
>  
>  static void broadwell_init_clock_gating(struct drm_device *dev)
> @@ -6916,6 +6920,10 @@ static void broadwell_init_clock_gating(struct drm_device *dev)
>  	 */
>  	I915_WRITE(HSW_GTT_CACHE_EN, GTT_CACHE_EN_ALL);
>  
> +	/* WaKVMNotificationOnConfigChange:bdw */
> +	I915_WRITE(CHICKEN_PAR2_1, I915_READ(CHICKEN_PAR2_1)
> +		   | KVM_CONFIG_CHANGE_NOTIFICATION_SELECT);
> +
>  	lpt_init_clock_gating(dev);
>  }
>  
> -- 
> 2.5.0
>
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