diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index f60485906f7ebcef073d53f5ee8b4866e0c2ee8a..670db5073d708ed786fdbccd9c538b1cff41fe2c 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -4658,6 +4658,79 @@ static const struct file_operations i915_hpd_storm_ctl_fops = {
.write = i915_hpd_storm_ctl_write
};
+static int i915_hpd_short_storm_ctl_show(struct seq_file *m, void *data)
+{
+ struct drm_i915_private *dev_priv = m->private;
+
+ seq_printf(m, "Enabled: %s\n",
+ yesno(dev_priv->hotplug.hpd_short_storm_enabled));
+
+ return 0;
+}
+
+static int
+i915_hpd_short_storm_ctl_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, i915_hpd_short_storm_ctl_show,
+ inode->i_private);
+}
+
+static ssize_t i915_hpd_short_storm_ctl_write(struct file *file,
+ const char __user *ubuf,
+ size_t len, loff_t *offp)
+{
+ struct seq_file *m = file->private_data;
+ struct drm_i915_private *dev_priv = m->private;
+ struct i915_hotplug *hotplug = &dev_priv->hotplug;
+ char *newline;
+ char tmp[16];
+ int i;
+ bool new_state;
+
+ if (len >= sizeof(tmp))
+ return -EINVAL;
+
+ if (copy_from_user(tmp, ubuf, len))
+ return -EFAULT;
+
+ tmp[len] = '\0';
+
+ /* Strip newline, if any */
+ newline = strchr(tmp, '\n');
+ if (newline)
+ *newline = '\0';
+
+ /* Reset to the "default" state for this system */
+ if (strcmp(tmp, "reset") == 0)
+ new_state = !HAS_DP_MST(dev_priv);
+ else if (kstrtobool(tmp, &new_state) != 0)
+ return -EINVAL;
+
+ DRM_DEBUG_KMS("%sabling HPD short storm detection\n",
+ new_state ? "En" : "Dis");
+
+ spin_lock_irq(&dev_priv->irq_lock);
+ hotplug->hpd_short_storm_enabled = new_state;
+ /* Reset the HPD storm stats so we don't accidentally trigger a storm */
+ for_each_hpd_pin(i)
+ hotplug->stats[i].count = 0;
+ spin_unlock_irq(&dev_priv->irq_lock);
+
+ /* Re-enable hpd immediately if we were in an irq storm */
+ flush_delayed_work(&dev_priv->hotplug.reenable_work);
+
+ return len;
+}
+
+static const struct file_operations i915_hpd_short_storm_ctl_fops = {
+ .owner = THIS_MODULE,
+ .open = i915_hpd_short_storm_ctl_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+ .write = i915_hpd_short_storm_ctl_write,
+};
+
static int i915_drrs_ctl_set(void *data, u64 val)
{
struct drm_i915_private *dev_priv = data;
@@ -4865,6 +4938,7 @@ static const struct i915_debugfs_files {
{"i915_guc_log_level", &i915_guc_log_level_fops},
{"i915_guc_log_relay", &i915_guc_log_relay_fops},
{"i915_hpd_storm_ctl", &i915_hpd_storm_ctl_fops},
+ {"i915_hpd_short_storm_ctl", &i915_hpd_short_storm_ctl_fops},
{"i915_ipc_status", &i915_ipc_status_fops},
{"i915_drrs_ctl", &i915_drrs_ctl_fops},
{"i915_edp_psr_debug", &i915_edp_psr_debug_fops}
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 2a88a7eb871ba36440363d54c75b1e69f7458ef1..0c8438de3c1bb8c1148460b7eba8da7ec872a6c2 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -283,7 +283,8 @@ enum hpd_pin {
#define for_each_hpd_pin(__pin) \
for ((__pin) = (HPD_NONE + 1); (__pin) < HPD_NUM_PINS; (__pin)++)
-#define HPD_STORM_DEFAULT_THRESHOLD 5
+/* Threshold == 5 for long IRQs, 50 for short */
+#define HPD_STORM_DEFAULT_THRESHOLD 50
struct i915_hotplug {
struct work_struct hotplug_work;
@@ -308,6 +309,8 @@ struct i915_hotplug {
bool poll_enabled;
unsigned int hpd_storm_threshold;
+ /* Whether or not to count short HPD IRQs in HPD storms */
+ u8 hpd_short_storm_enabled;
/*
* if we get a HPD irq from DP and a HPD irq from non-DP
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 5d1f5372338848bd9e28830b7277db565446c008..d7e47d6082de6c360e79c5404d82d5466876b41c 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -4863,6 +4863,13 @@ void intel_irq_init(struct drm_i915_private *dev_priv)
dev_priv->display_irqs_enabled = false;
dev_priv->hotplug.hpd_storm_threshold = HPD_STORM_DEFAULT_THRESHOLD;
+ /* If we have MST support, we want to avoid doing short HPD IRQ storm
+ * detection, as short HPD storms will occur as a natural part of
+ * sideband messaging with MST.
+ * On older platforms however, IRQ storms can occur with both long and
+ * short pulses, as seen on some G4x systems.
+ */
+ dev_priv->hotplug.hpd_short_storm_enabled = !HAS_DP_MST(dev_priv);
dev->driver->get_vblank_timestamp = drm_calc_vbltimestamp_from_scanoutpos;
dev->driver->get_scanout_position = i915_get_crtc_scanoutpos;
diff --git a/drivers/gpu/drm/i915/intel_hotplug.c b/drivers/gpu/drm/i915/intel_hotplug.c
index d642c0795452e4282cdff9e205b71c52c8473117..42e61e10f517371f2e86b53368029a620353bee0 100644
--- a/drivers/gpu/drm/i915/intel_hotplug.c
+++ b/drivers/gpu/drm/i915/intel_hotplug.c
@@ -114,34 +114,46 @@ enum hpd_pin intel_hpd_pin_default(struct drm_i915_private *dev_priv,
#define HPD_STORM_REENABLE_DELAY (2 * 60 * 1000)
/**
- * intel_hpd_irq_storm_detect - gather stats and detect HPD irq storm on a pin
+ * intel_hpd_irq_storm_detect - gather stats and detect HPD IRQ storm on a pin
* @dev_priv: private driver data pointer
* @pin: the pin to gather stats on
+ * @long_hpd: whether the HPD IRQ was long or short
*
- * Gather stats about HPD irqs from the specified @pin, and detect irq
+ * Gather stats about HPD IRQs from the specified @pin, and detect IRQ
* storms. Only the pin specific stats and state are changed, the caller is
* responsible for further action.
*
- * The number of irqs that are allowed within @HPD_STORM_DETECT_PERIOD is
+ * The number of IRQs that are allowed within @HPD_STORM_DETECT_PERIOD is
* stored in @dev_priv->hotplug.hpd_storm_threshold which defaults to
- * @HPD_STORM_DEFAULT_THRESHOLD. If this threshold is exceeded, it's
- * considered an irq storm and the irq state is set to @HPD_MARK_DISABLED.
+ * @HPD_STORM_DEFAULT_THRESHOLD. Long IRQs count as +10 to this threshold, and
+ * short IRQs count as +1. If this threshold is exceeded, it's considered an
+ * IRQ storm and the IRQ state is set to @HPD_MARK_DISABLED.
+ *
+ * By default, most systems will only count long IRQs towards
+ * &dev_priv->hotplug.hpd_storm_threshold. However, some older systems also
+ * suffer from short IRQ storms and must also track these. Because short IRQ
+ * storms are naturally caused by sideband interactions with DP MST devices,
+ * short IRQ detection is only enabled for systems without DP MST support.
+ * Systems which are new enough to support DP MST are far less likely to
+ * suffer from IRQ storms at all, so this is fine.
*
* The HPD threshold can be controlled through i915_hpd_storm_ctl in debugfs,
* and should only be adjusted for automated hotplug testing.
*
- * Return true if an irq storm was detected on @pin.
+ * Return true if an IRQ storm was detected on @pin.
*/
static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
- enum hpd_pin pin)
+ enum hpd_pin pin, bool long_hpd)
{
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 increment = long_hpd ? 10 : 1;
const int threshold = hpd->hpd_storm_threshold;
bool storm = false;
- if (!threshold)
+ if (!threshold ||
+ (!long_hpd && !dev_priv->hotplug.hpd_short_storm_enabled))
return false;
if (!time_in_range(jiffies, start, end)) {
@@ -149,7 +161,8 @@ static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
hpd->stats[pin].count = 0;
}
- if (++hpd->stats[pin].count > threshold) {
+ hpd->stats[pin].count += increment;
+ 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;
@@ -409,28 +422,24 @@ void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
for_each_intel_encoder(&dev_priv->drm, encoder) {
enum hpd_pin pin = encoder->hpd_pin;
bool has_hpd_pulse = intel_encoder_has_hpd_pulse(encoder);
+ bool long_hpd = true;
if (!(BIT(pin) & pin_mask))
continue;
if (has_hpd_pulse) {
- bool long_hpd = long_mask & BIT(pin);
enum port port = encoder->port;
+ long_hpd = long_mask & BIT(pin);
+
DRM_DEBUG_DRIVER("digital hpd port %c - %s\n", port_name(port),
long_hpd ? "long" : "short");
- /*
- * For long HPD pulses we want to have the digital queue happen,
- * but we still want HPD storm detection to function.
- */
queue_dig = true;
- if (long_hpd) {
+ if (long_hpd)
dev_priv->hotplug.long_port_mask |= (1 << port);
- } else {
- /* for short HPD just trigger the digital queue */
+ else
dev_priv->hotplug.short_port_mask |= (1 << port);
- continue;
- }
+
}
if (dev_priv->hotplug.stats[pin].state == HPD_DISABLED) {
@@ -453,9 +462,10 @@ void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
queue_hp = true;
}
- if (intel_hpd_irq_storm_detect(dev_priv, pin)) {
+ if (intel_hpd_irq_storm_detect(dev_priv, pin, long_hpd)) {
dev_priv->hotplug.event_bits &= ~BIT(pin);
storm_detected = true;
+ queue_hp = true;
}
}