From: Lyude Paul Date: Tue, 6 Nov 2018 21:30:14 +0000 (-0500) Subject: drm/i915: Fix threshold check in intel_hpd_irq_storm_detect() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a4af7889eb31f52f4fc4d8fae4e66eae04140125;p=linux.git drm/i915: Fix threshold check in intel_hpd_irq_storm_detect() Currently in intel_hpd_irq_storm_detect() when we detect that the last recorded hotplug wasn't within the period defined by HPD_STORM_DETECT_DELAY, we make the mistake of resetting the HPD count to 0 without incrementing it. This results in us only enabling storm detection when we go +2 above the threshold, e.g. an HPD threshold of 5 would not trigger a storm until we reach a total of 7 hotplugs. So: rework the code a bit so we reset the HPD count when HPD_STORM_DETECT_DELAY has passed, then increment the count afterwards. Also, clean things up a bit to make it easier to undertand. Signed-off-by: Lyude Paul Reviewed-by: Ville Syrjälä Cc: Rodrigo Vivi Link: https://patchwork.freedesktop.org/patch/msgid/20181106213017.14563-4-lyude@redhat.com --- diff --git a/drivers/gpu/drm/i915/intel_hotplug.c b/drivers/gpu/drm/i915/intel_hotplug.c index 8326900a311e4..c11d73de16f2b 100644 --- a/drivers/gpu/drm/i915/intel_hotplug.c +++ b/drivers/gpu/drm/i915/intel_hotplug.c @@ -135,24 +135,27 @@ enum hpd_pin intel_hpd_pin_default(struct drm_i915_private *dev_priv, static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv, enum hpd_pin pin) { - unsigned long start = dev_priv->hotplug.stats[pin].last_jiffies; + struct i915_hotplug *hpd = &dev_priv->hotplug; + unsigned long start = hpd->stats[pin].last_jiffies; unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD); - const int threshold = dev_priv->hotplug.hpd_storm_threshold; + const int threshold = hpd->hpd_storm_threshold; bool storm = false; + if (!threshold) + return false; + if (!time_in_range(jiffies, start, end)) { - dev_priv->hotplug.stats[pin].last_jiffies = jiffies; - dev_priv->hotplug.stats[pin].count = 0; - DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: 0\n", pin); - } else if (dev_priv->hotplug.stats[pin].count > threshold && - threshold) { - dev_priv->hotplug.stats[pin].state = HPD_MARK_DISABLED; + hpd->stats[pin].last_jiffies = jiffies; + hpd->stats[pin].count = 0; + } + + if (++hpd->stats[pin].count > threshold) { + hpd->stats[pin].state = HPD_MARK_DISABLED; DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", pin); storm = true; } else { - dev_priv->hotplug.stats[pin].count++; DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: %d\n", pin, - dev_priv->hotplug.stats[pin].count); + hpd->stats[pin].count); } return storm;