Re: [PATCH 6/7] drm/i915: Restart RPS using the same RP_CONTROL as from initialisation

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

Chris Wilson <chris@chris-wilson.co.uk> writes:

> During initialisation, we set different flags for different
> architectures - these should be preserved when we reload the RPS
> thresholds. If we use a mmio read, it will first ensure that the
> threshold registers are written before we apply the latch in RP_CONTROL.
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
> Cc: stable@vger.kernel.org

This will change how the valleyview will do the DOWN_IDLE,
due to readback you will get a GEN6_RP_DOWN_IDLE_CONT.

I can't think of why we would like to keep that behaviour
as the IDLE_CONT setup is a twart in my opinion.

If you agree with the above, substitute the IDLE_CONT in
valleview setup and you can add,

Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>

> ---
>  drivers/gpu/drm/i915/intel_pm.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 3041cd4988a6..d37e95b3525d 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4884,13 +4884,9 @@ static void gen6_set_rps_thresholds(struct drm_i915_private *dev_priv, u8 val)
>  		      GT_INTERVAL_FROM_US(dev_priv,
>  					  ei_down * threshold_down / 100));
>  
> +	/* Restart RPS to reload the thresholds */
>  	I915_WRITE_FW(GEN6_RP_CONTROL,
> -		      GEN6_RP_MEDIA_TURBO |
> -		      GEN6_RP_MEDIA_HW_NORMAL_MODE |
> -		      GEN6_RP_MEDIA_IS_GFX |
> -		      GEN6_RP_ENABLE |
> -		      GEN6_RP_UP_BUSY_AVG |
> -		      GEN6_RP_DOWN_IDLE_AVG);
> +		      I915_READ_FW(GEN6_RP_CONTROL) | GEN6_RP_ENABLE);
>  
>  	intel_uncore_forcewake_put__locked(dev_priv, FORCEWAKE_ALL);
>  	spin_unlock_irq(&dev_priv->uncore.lock);
> -- 
> 2.11.0