drm/i915/debugfs: Add i915_hpd_storm_ctl
This adds a file in i915's debugfs directory that allows userspace to
manually control HPD storm detection. This is mainly for hotplugging
tests, where we might want to test HPD storm functionality or disable
storm detection to speed up hotplugging tests without breaking anything.
Changes since v1:
- Make HPD storm interval configurable
- Misc code cleanup
Signed-off-by: Lyude <lyude@redhat.com>
Acked-by: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Tomeu Vizoso <tomeu@tomeuvizoso.net>
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 6415277..cd023fd 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -4653,6 +4653,81 @@ static int i915_forcewake_create(struct dentry *root, struct drm_minor *minor)
return drm_add_fake_info_node(minor, ent, &i915_forcewake_fops);
}
+static int i915_hpd_storm_ctl_show(struct seq_file *m, void *data)
+{
+ struct drm_i915_private *dev_priv = m->private;
+ struct i915_hotplug *hotplug = &dev_priv->hotplug;
+
+ seq_printf(m, "Threshold: %d\n", hotplug->hpd_storm_threshold);
+ seq_printf(m, "Detected: %s\n",
+ yesno(delayed_work_pending(&hotplug->reenable_work)));
+
+ return 0;
+}
+
+static ssize_t i915_hpd_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;
+ unsigned int new_threshold;
+ int i;
+ char *newline;
+ char tmp[16];
+
+ 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';
+
+ if (strcmp(tmp, "reset") == 0)
+ new_threshold = HPD_STORM_DEFAULT_THRESHOLD;
+ else if (kstrtouint(tmp, 10, &new_threshold) != 0)
+ return -EINVAL;
+
+ if (new_threshold > 0)
+ DRM_DEBUG_KMS("Setting HPD storm detection threshold to %d\n",
+ new_threshold);
+ else
+ DRM_DEBUG_KMS("Disabling HPD storm detection\n");
+
+ spin_lock_irq(&dev_priv->irq_lock);
+ hotplug->hpd_storm_threshold = new_threshold;
+ /* 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 int i915_hpd_storm_ctl_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, i915_hpd_storm_ctl_show, inode->i_private);
+}
+
+static const struct file_operations i915_hpd_storm_ctl_fops = {
+ .owner = THIS_MODULE,
+ .open = i915_hpd_storm_ctl_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+ .write = i915_hpd_storm_ctl_write
+};
+
static int i915_debugfs_create(struct dentry *root,
struct drm_minor *minor,
const char *name,
@@ -4746,7 +4821,8 @@ static const struct i915_debugfs_files {
{"i915_dp_test_data", &i915_displayport_test_data_fops},
{"i915_dp_test_type", &i915_displayport_test_type_fops},
{"i915_dp_test_active", &i915_displayport_test_active_fops},
- {"i915_guc_log_control", &i915_guc_log_control_fops}
+ {"i915_guc_log_control", &i915_guc_log_control_fops},
+ {"i915_hpd_storm_ctl", &i915_hpd_storm_ctl_fops}
};
int i915_debugfs_register(struct drm_i915_private *dev_priv)