From a4af7889eb31f52f4fc4d8fae4e66eae04140125 Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Tue, 6 Nov 2018 16:30:14 -0500 Subject: [PATCH] drm/i915: Fix threshold check in intel_hpd_irq_storm_detect() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 --- drivers/gpu/drm/i915/intel_hotplug.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_hotplug.c b/drivers/gpu/drm/i915/intel_hotplug.c index 8326900a311e..c11d73de16f2 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;