Re: [PATCH] drm/i915: Add messages usful for HPD strom detection debugging

[Jani Nikula <jani.nikula@linux.intel.com>]

On Fri, 26 Jul 2013, Egbert Eich <eich@suse.de> wrote:
> For HPD storm detection we now mask out individual interrupt source
> bits. We have already seen a case where HPD interrupt enable bits
> were assigned to the wrong pins. To track these conditions more
> easily add some debugging messages.

The code seems okay, please spellcheck the subject and debug prints! :)

BR,
Jani.

>
> Signed-off-by: Egbert Eich <eich@suse.de>
> ---
>  drivers/gpu/drm/i915/i915_irq.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index ee3e49c..1f3a971 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -919,6 +919,10 @@ static inline void intel_hpd_irq_handler(struct drm_device *dev,
>  	spin_lock(&dev_priv->irq_lock);
>  	for (i = 1; i < HPD_NUM_PINS; i++) {
>  
> +		WARN(((hpd[i] & hotplug_trigger) &&
> +		      dev_priv->hpd_stats[i].hpd_mark != HPD_ENABLED),
> +		     "Received HPD intterupt although disabled\n");
> +
>  		if (!(hpd[i] & hotplug_trigger) ||
>  		    dev_priv->hpd_stats[i].hpd_mark != HPD_ENABLED)
>  			continue;
> @@ -929,6 +933,7 @@ static inline void intel_hpd_irq_handler(struct drm_device *dev,
>  				   + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD))) {
>  			dev_priv->hpd_stats[i].hpd_last_jiffies = jiffies;
>  			dev_priv->hpd_stats[i].hpd_cnt = 0;
> +			DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: 0\n", i);
>  		} else if (dev_priv->hpd_stats[i].hpd_cnt > HPD_STORM_THRESHOLD) {
>  			dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
>  			dev_priv->hpd_event_bits &= ~(1 << i);
> @@ -936,6 +941,8 @@ static inline void intel_hpd_irq_handler(struct drm_device *dev,
>  			storm_detected = true;
>  		} else {
>  			dev_priv->hpd_stats[i].hpd_cnt++;
> +			DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: %d\n", i,
> +				      dev_priv->hpd_stats[i].hpd_cnt);
>  		}
>  	}
>  
> -- 
> 1.8.1.4
>
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-- 
Jani Nikula, Intel Open Source Technology Center