commit 2e0965b06d90b9dba76198d026c4c2ee04443aca
author Jyri Sarha <jsarha@ti.com> Tue Sep 06 17:25:08 2016 +0300
committer Jyri Sarha <jsarha@ti.com> Wed Sep 07 15:54:43 2016 +0300
tree ccef377ba06e82d714cbc0add7933fb0caadb561
parent 6c94c71400fbb630549611e17b430458c1c00cf8

drm/tilcdc: WARN if CRTC is touched without CRTC lock

WARN if CRTC is touched without CRTC lock. The crtc functions should
not be called simultaneously from multiple threads. Having the DRM
CRTC lock should take care of that.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/gpu/drm/tilcdc/tilcdc_crtc.c

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
index c1cbabc..639821f 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
@@ -153,6 +153,8 @@
 	struct drm_device *dev = crtc->dev;
 	struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
 
+	WARN_ON(!drm_modeset_is_locked(&crtc->mutex));
+
 	if (tilcdc_crtc->enabled)
 		return;
 
@@ -177,6 +179,8 @@
 	struct drm_device *dev = crtc->dev;
 	struct tilcdc_drm_private *priv = dev->dev_private;
 
+	WARN_ON(!drm_modeset_is_locked(&crtc->mutex));
+
 	if (!tilcdc_crtc->enabled)
 		return;
 
@@ -249,6 +253,8 @@
 	struct drm_device *dev = crtc->dev;
 	unsigned long flags;
 
+	WARN_ON(!drm_modeset_is_locked(&crtc->mutex));
+
 	if (tilcdc_crtc->event) {
 		dev_err(dev->dev, "already pending page flip!\n");
 		return -EBUSY;
@@ -353,6 +359,8 @@
 	struct drm_display_mode *mode = &crtc->state->adjusted_mode;
 	struct drm_framebuffer *fb = crtc->primary->state->fb;
 
+	WARN_ON(!drm_modeset_is_locked(&crtc->mutex));
+
 	if (WARN_ON(!info))
 		return;