[Intel-gfx] i915 irq storm mitigation in 3.10

[Jan Niggemann]

Hi Egbert,

Am 23.07.2013 13:26, schrieb Egbert Eich:
> I've looked at the logs a bit more. Here's a patch adding some more
> debug information. Would you please apply this to your 3.10 kernel
> and generate a log file the same way as you did before.
> The driver will be even more chatty - but I don't expect any problems
> from this.

> diff --git a/drivers/gpu/drm/i915/i915_irq.c
> b/drivers/gpu/drm/i915/i915_irq.c
> index e43d809..46bb77c 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -919,6 +919,11 @@ 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++) {
>
> +		if (IS_G4X(dev) && (hpd[i] & hotplug_trigger) &&
> +		    dev_priv->hpd_stats[i].hpd_mark != HPD_ENABLED)
> +			DRM_DEBUG_KMS("Received HPD intterupt although disabled\n",
> +				      I915_READ(PORT_HOTPLUG_EN));
> +
>  		if (!(hpd[i] & hotplug_trigger) ||
>  		    dev_priv->hpd_stats[i].hpd_mark != HPD_ENABLED)
>  			continue;
> @@ -929,6 +934,8 @@ 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 - jiffies: %d\n", 
> i,
> +				      dev_priv->hpd_stats[i].hpd_last_jiffies);
>  		} 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 +943,8 @@ 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);
>  		}
>  	}
I applied this patch (but not the one you sent on Monday), recompiled 
and logged:
uncompressed (8,2M) http://files.hz6.de/kern_20130724.log
bz2 (288 KB) http://files.hz6.de/kern_20130724.log.bz2

Hope this helps,
Regards
jan