drm/nouveau: Handle fbcon suspend/resume in seperate worker

[ Upstream commit 15266ae ] Resuming from RPM can happen while already holding dev->mode_config.mutex. This means we can't actually handle fbcon in any RPM resume workers, since restoring fbcon requires grabbing dev->mode_config.mutex again. So move the fbcon suspend/resume code into it's own worker, and rely on that instead to avoid deadlocking. This fixes more deadlocks for runtime suspending the GPU on the ThinkPad W541. Reproduction recipe: - Get a machine with both optimus and a nvidia card with connectors attached to it - Wait for the nvidia GPU to suspend - Attempt to manually reprobe any of the connectors on the nvidia GPU using sysfs - *deadlock* [airlied: use READ_ONCE to address Hans's comment] Signed-off-by: Lyude <[email protected]> Cc: Hans de Goede <[email protected]> Cc: Kilian Singer <[email protected]> Cc: Lukas Wunner <[email protected]> Cc: David Airlie <[email protected]> Signed-off-by: Dave Airlie <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
TechNexion · Jun 17, 2017 · c7a29cf · c7a29cf
1 parent d2beb1a
commit c7a29cf
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Showing 2 changed files with 36 additions and 9 deletions.
diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h b/drivers/gpu/drm/nouveau/nouveau_drv.h
@@ -164,6 +164,8 @@ struct nouveau_drm {
 	struct nouveau_display *display;
 	struct backlight_device *backlight;
 	struct work_struct hpd_work;
+	struct work_struct fbcon_work;
+	int fbcon_new_state;
 #ifdef CONFIG_ACPI
 	struct notifier_block acpi_nb;
 #endif

diff --git a/drivers/gpu/drm/nouveau/nouveau_fbcon.c b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
@@ -491,19 +491,43 @@ static const struct drm_fb_helper_funcs nouveau_fbcon_helper_funcs = {
 	.fb_probe = nouveau_fbcon_create,
 };
 
+static void
+nouveau_fbcon_set_suspend_work(struct work_struct *work)
+{
+	struct nouveau_drm *drm = container_of(work, typeof(*drm), fbcon_work);
+	int state = READ_ONCE(drm->fbcon_new_state);
+
+	if (state == FBINFO_STATE_RUNNING)
+		pm_runtime_get_sync(drm->dev->dev);
+
+	console_lock();
+	if (state == FBINFO_STATE_RUNNING)
+		nouveau_fbcon_accel_restore(drm->dev);
+	drm_fb_helper_set_suspend(&drm->fbcon->helper, state);
+	if (state != FBINFO_STATE_RUNNING)
+		nouveau_fbcon_accel_save_disable(drm->dev);
+	console_unlock();
+
+	if (state == FBINFO_STATE_RUNNING) {
+		pm_runtime_mark_last_busy(drm->dev->dev);
+		pm_runtime_put_sync(drm->dev->dev);
+	}
+}
+
 void
 nouveau_fbcon_set_suspend(struct drm_device *dev, int state)
 {
 	struct nouveau_drm *drm = nouveau_drm(dev);
-	if (drm->fbcon) {
-		console_lock();
-		if (state == FBINFO_STATE_RUNNING)
-			nouveau_fbcon_accel_restore(dev);
-		drm_fb_helper_set_suspend(&drm->fbcon->helper, state);
-		if (state != FBINFO_STATE_RUNNING)
-			nouveau_fbcon_accel_save_disable(dev);
-		console_unlock();
-	}
+
+	if (!drm->fbcon)
+		return;
+
+	drm->fbcon_new_state = state;
+	/* Since runtime resume can happen as a result of a sysfs operation,
+	 * it's possible we already have the console locked. So handle fbcon
+	 * init/deinit from a seperate work thread
+	 */
+	schedule_work(&drm->fbcon_work);
 }
 
 int
@@ -524,6 +548,7 @@ nouveau_fbcon_init(struct drm_device *dev)
 
 	fbcon->dev = dev;
 	drm->fbcon = fbcon;
+	INIT_WORK(&drm->fbcon_work, nouveau_fbcon_set_suspend_work);
 
 	drm_fb_helper_prepare(dev, &fbcon->helper, &nouveau_fbcon_helper_funcs);