[Intel-gfx] [PATCH 9/9] drm/i915: set FORCE_ARB_IDLE_PLANES workaround

[Ville Syrjälä]

On Fri, May 03, 2013 at 05:23:45PM -0300, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
> 
> Commit 1544d9d57396d5c0c6b7644ed5ae1f4d6caad07a added a workaround
> inside haswell_init_clock_gating and mentioned it is "a workaround for
> early silicon revisions and should be removed later". This workaround
> is documented in bit 31 of PRI_CTL. I asked Arthur and he mentioned
> that setting FORCE_ARB_IDLE_PLANES replaces that workaround for the
> newer machines. So use the new one.
> 
> Also notice that there's still another workaround for PRI_CTL that
> involves WM_DBG, but it's not the one we're reverting. And notice that
> we were previously setting WM_DBG_DISALLOW_MULTIPIPE_LP which disables
> the LP watermarks when more than one pipe is used, and we really don't
> want this because we need the LP watermarks if we want to reach deeper
> PC states.
> 
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

> ---
>  drivers/gpu/drm/i915/i915_reg.h |    3 +++
>  drivers/gpu/drm/i915/intel_pm.c |   10 ++--------
>  2 files changed, 5 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index aec569f..5879f23 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -3697,6 +3697,9 @@
>  # define CHICKEN3_DGMG_REQ_OUT_FIX_DISABLE	(1 << 5)
>  # define CHICKEN3_DGMG_DONE_FIX_DISABLE		(1 << 2)
>  
> +#define CHICKEN_PAR1_1		0x42080
> +#define  FORCE_ARB_IDLE_PLANES	(1 << 14)
> +
>  #define DISP_ARB_CTL	0x45000
>  #define  DISP_TILE_SURFACE_SWIZZLING	(1<<13)
>  #define  DISP_FBC_WM_DIS		(1<<15)
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index b56de92..2297476 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4042,14 +4042,8 @@ static void haswell_init_clock_gating(struct drm_device *dev)
>  	/* WaSwitchSolVfFArbitrationPriority */
>  	I915_WRITE(GAM_ECOCHK, I915_READ(GAM_ECOCHK) | HSW_ECOCHK_ARB_PRIO_SOL);
>  
> -	/* XXX: This is a workaround for early silicon revisions and should be
> -	 * removed later.
> -	 */
> -	I915_WRITE(WM_DBG,
> -			I915_READ(WM_DBG) |
> -			WM_DBG_DISALLOW_MULTIPLE_LP |
> -			WM_DBG_DISALLOW_SPRITE |
> -			WM_DBG_DISALLOW_MAXFIFO);
> +	I915_WRITE(CHICKEN_PAR1_1,
> +		   I915_READ(CHICKEN_PAR1_1) | FORCE_ARB_IDLE_PLANES);
>  
>  	lpt_init_clock_gating(dev);
>  }
> -- 
> 1.7.10.4
> 
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-- 
Ville Syrjälä
Intel OTC