Re: [PATCH 22/24] drm/i915/gen9: Add WaFbcWakeMemOn

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org, Paulo Zanoni <paulo.r.zanoni@intel.com>
Subject: Re: [PATCH 22/24] drm/i915/gen9: Add WaFbcWakeMemOn
Date: Wed, 1 Jun 2016 18:05:47 +0300	[thread overview]
Message-ID: <20160601150547.GG4329@intel.com> (raw)
In-Reply-To: <1464359224-11436-23-git-send-email-mika.kuoppala@intel.com>

On Fri, May 27, 2016 at 05:27:02PM +0300, Mika Kuoppala wrote:
> Set bit 8 in 0x43224 to prevent screen corruption and system
> hangs on high memory bandwidth conditions. The same wa also suggest
> setting bit 31 on ARB_CTL. According to another workaround we gain
> better idle power savings when FBC is enabled.
> 
> v2: use correct workaround name
> 
> References: HSD#2137218, HSD#2227171, HSD#2136579, BSID#883
> Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
> Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_reg.h | 2 ++
>  drivers/gpu/drm/i915/intel_pm.c | 9 +++++++--
>  2 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 280d2137f90f..2f3a3960f5f7 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -2208,6 +2208,7 @@ enum skl_disp_power_wells {
>  #define ILK_DPFC_STATUS		_MMIO(0x43210)
>  #define ILK_DPFC_FENCE_YOFF	_MMIO(0x43218)
>  #define ILK_DPFC_CHICKEN	_MMIO(0x43224)
> +#define   ILK_DPFC_DISABLE_DUMMY0 (1<<8)
>  #define ILK_FBC_RT_BASE		_MMIO(0x2128)
>  #define   ILK_FBC_RT_VALID	(1<<0)
>  #define   SNB_FBC_FRONT_BUFFER	(1<<1)
> @@ -6053,6 +6054,7 @@ enum skl_disp_power_wells {
>  #define CHICKEN_PIPESL_1(pipe) _MMIO_PIPE(pipe, _CHICKEN_PIPESL_1_A, _CHICKEN_PIPESL_1_B)
>  
>  #define DISP_ARB_CTL	_MMIO(0x45000)
> +#define  DISP_FBC_MEMORY_WAKE		(1<<31)
>  #define  DISP_TILE_SURFACE_SWIZZLING	(1<<13)
>  #define  DISP_FBC_WM_DIS		(1<<15)
>  #define DISP_ARB_CTL2	_MMIO(0x45004)
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index b2acb82b302b..6d9cf487ea40 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -70,8 +70,13 @@ static void gen9_init_clock_gating(struct drm_device *dev)
>  		   I915_READ(GEN8_CHICKEN_DCPR_1) | MASK_WAKEMEM);
>  
>  	/* WaFbcTurnOffFbcWatermark:skl,bxt,kbl */
> -	I915_WRITE(DISP_ARB_CTL,
> -		   I915_READ(DISP_ARB_CTL) | DISP_FBC_WM_DIS);
> +	/* WaFbcWakeMemOn:skl,bxt,kbl */
> +	I915_WRITE(DISP_ARB_CTL, I915_READ(DISP_ARB_CTL) |
> +		   DISP_FBC_WM_DIS |
> +		   DISP_FBC_MEMORY_WAKE);
> +
> +	I915_WRITE(ILK_DPFC_CHICKEN, I915_READ(ILK_DPFC_CHICKEN) |
> +		   ILK_DPFC_DISABLE_DUMMY0);

I think we might have two partially overlapping w/as here:
WaFbcWakeMemOn and WaFbcHighMemBwCorruptionAvoidance. Not sure if the
latter applies to all of KBL. w/a db says all, bspec says a0,b0 only.

Might want to add the other w/a name as well at least. With that this is
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

>  }
>  
>  static void bxt_init_clock_gating(struct drm_device *dev)
> -- 
> 2.5.0
> 
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-- 
Ville Syrjälä
Intel OTC
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