Re: [PATCH] drm/i915: Remove wait for for punit to updates freq.

From: Jesse Barnes <jbarnes@virtuousgeek.org>
To: deepak.s@linux.intel.com, intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: Remove wait for for punit to updates freq.
Date: Tue, 28 Apr 2015 11:16:29 -0700	[thread overview]
Message-ID: <553FCE7D.6090806@virtuousgeek.org> (raw)
In-Reply-To: <1425528503-7760-1-git-send-email-deepak.s@linux.intel.com>

On 03/04/2015 08:08 PM, deepak.s@linux.intel.com wrote:
> From: Deepak S <deepak.s@linux.intel.com>
> 
> When GPU is idle on VLV, Request freq to punit should be good enough to
> get the voltage back to VNN. Also, make sure gfx clock force applies
> before requesting the freq fot vlv.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=75244
> suggested-by: Jesse Barnes <jbarnes@virtuousgeek.org>
> Signed-off-by: Deepak S <deepak.s@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 20 ++++----------------
>  1 file changed, 4 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index e710b43..2e1ed07 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -3894,7 +3894,7 @@ static void valleyview_set_rps(struct drm_device *dev, u8 val)
>   * * If Gfx is Idle, then
>   * 1. Mask Turbo interrupts
>   * 2. Bring up Gfx clock
> - * 3. Change the freq to Rpn and wait till P-Unit updates freq
> + * 3. Request the freq to Rpn.
>   * 4. Clear the Force GFX CLK ON bit so that Gfx can down
>   * 5. Unmask Turbo interrupts
>  */
> @@ -3902,8 +3902,8 @@ static void vlv_set_rps_idle(struct drm_i915_private *dev_priv)
>  {
>  	struct drm_device *dev = dev_priv->dev;
>  
> -	/* CHV and latest VLV don't need to force the gfx clock */
> -	if (IS_CHERRYVIEW(dev) || dev->pdev->revision >= 0xd) {
> +	/* CHV don't need to force the gfx clock */
> +	if (IS_CHERRYVIEW(dev)) {
>  		valleyview_set_rps(dev_priv->dev, dev_priv->rps.min_freq_softlimit);
>  		return;
>  	}
> @@ -3920,20 +3920,8 @@ static void vlv_set_rps_idle(struct drm_i915_private *dev_priv)
>  		   gen6_sanitize_rps_pm_mask(dev_priv, ~0));
>  
>  	vlv_force_gfx_clock(dev_priv, true);
> -
> -	dev_priv->rps.cur_freq = dev_priv->rps.min_freq_softlimit;
> -
> -	vlv_punit_write(dev_priv, PUNIT_REG_GPU_FREQ_REQ,
> -					dev_priv->rps.min_freq_softlimit);
> -
> -	if (wait_for(((vlv_punit_read(dev_priv, PUNIT_REG_GPU_FREQ_STS))
> -				& GENFREQSTATUS) == 0, 100))
> -		DRM_ERROR("timed out waiting for Punit\n");
> -
> +	valleyview_set_rps(dev_priv->dev, dev_priv->rps.min_freq_softlimit);
>  	vlv_force_gfx_clock(dev_priv, false);
> -
> -	I915_WRITE(GEN6_PMINTRMSK,
> -		   gen6_rps_pm_mask(dev_priv, dev_priv->rps.cur_freq));
>  }
>  
>  void gen6_rps_idle(struct drm_i915_private *dev_priv)
> 

Yeah I think this is fine (may need a rebase though, you can keep my r-b
if you do that in case Jani doesn't want to deal with the merge conflicts).

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
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