[Intel-gfx] [PATCH 15/35] drm/i915: Print the watermark latencies during init

[Paulo Zanoni]

2013/7/5  <ville.syrjala at linux.intel.com>:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> Seeing the watermark latency values in dmesg might help sometimes.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 37919df..5687957 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -2392,6 +2392,24 @@ static void intel_fixup_cur_wm_latency(struct drm_device *dev, uint16_t wm[5])
>                 wm[3] *= 2;
>  }
>
> +static void intel_print_wm_latency(struct drm_device *dev, const uint16_t wm[5])
> +{
> +       int level;
> +
> +       for (level = 0; level <= 4; level++) {
> +               unsigned int latency = wm[level];
> +
> +               if (latency == 0)
> +                       continue;

One of the cases that should be interesting to print is exactly when a
latency we expect to be non-zero is zero. Maybe you should do a simple
"switch" statement to get max_level depending on Gen number and print
everything from level 0 to max_level? Then if "latency == 0" we could
even promote the message to a DRM_ERROR?

> +
> +               if (level > 0)
> +                       latency *= 5;
> +
> +               DRM_DEBUG_KMS(" WM%d latency %u (%u.%u usec)\n",
> +                             level, wm[level], latency / 10, latency % 10);
> +       }
> +}
> +
>  static void intel_setup_wm_latency(struct drm_device *dev)
>  {
>         struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -2405,6 +2423,13 @@ static void intel_setup_wm_latency(struct drm_device *dev)
>
>         intel_fixup_spr_wm_latency(dev, dev_priv->wm.spr_latency);
>         intel_fixup_cur_wm_latency(dev, dev_priv->wm.cur_latency);
> +
> +       DRM_DEBUG_KMS("Primary watermark latencies:\n");
> +       intel_print_wm_latency(dev, dev_priv->wm.pri_latency);
> +       DRM_DEBUG_KMS("Sprite watermark latencies:\n");
> +       intel_print_wm_latency(dev, dev_priv->wm.spr_latency);
> +       DRM_DEBUG_KMS("Cursor watermark latencies:\n");
> +       intel_print_wm_latency(dev, dev_priv->wm.cur_latency);
>  }
>
>  static void hsw_compute_wm_parameters(struct drm_device *dev,
> --
> 1.8.1.5
>
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-- 
Paulo Zanoni