Re: [PATCH 1/2] drm/i915/vlv: use lower precision RC6 counter

[Ben Widawsky <ben@bwidawsk.net>]

On Thu, Sep 26, 2013 at 12:33:20PM -0700, Jesse Barnes wrote:
> And add some reg defines while we're at it.  Since the units of the RC6
> residency counter are actually in CZ clocks, we want to just use the
> high bits or we'll overflow too frequently.
> 
> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
> ---
>  drivers/gpu/drm/i915/i915_reg.h | 4 ++++
>  drivers/gpu/drm/i915/intel_pm.c | 5 ++++-
>  2 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 00fda45..cf995bb 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -4721,6 +4721,10 @@
>  						 GEN6_PM_RP_DOWN_TIMEOUT)
>  
>  #define GEN6_GT_GFX_RC6_LOCKED			0x138104
> +#define VLV_COUNTER_CONTROL			0x138104
> +#define   VLV_COUNT_RANGE_HIGH			(1<<15)
> +#define   VLV_MEDIA_RC6_COUNT_EN		(1<<1)
> +#define   VLV_RENDER_RC6_COUNT_EN		(1<<0)
>  #define GEN6_GT_GFX_RC6				0x138108
>  #define GEN6_GT_GFX_RC6p			0x13810C
>  #define GEN6_GT_GFX_RC6pp			0x138110
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index d27eda6..d8bdc98 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -3827,7 +3827,10 @@ static void valleyview_enable_rps(struct drm_device *dev)
>  	I915_WRITE(GEN6_RC6_THRESHOLD, 0xc350);
>  
>  	/* allows RC6 residency counter to work */
> -	I915_WRITE(0x138104, _MASKED_BIT_ENABLE(0x3));
> +	I915_WRITE(VLV_COUNTER_CONTROL,
> +		   _MASKED_BIT_ENABLE(VLV_COUNT_RANGE_HIGH |
> +				      VLV_MEDIA_RC6_COUNT_EN |
> +				      VLV_RENDER_RC6_COUNT_EN));
>  	if (intel_enable_rc6(dev) & INTEL_RC6_ENABLE)
>  		rc6_mode = GEN7_RC_CTL_TO_MODE;
>  	I915_WRITE(GEN6_RC_CONTROL, rc6_mode);

I wonder if the counters use power ie. only enable them when we are
using rc6.

Otherwise, it's:
Requested-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>

-- 
Ben Widawsky, Intel Open Source Technology Center