[PATCH 09/12] drm/irq: Lack of interrupt support in drm_vblank_on|off

[Daniel Vetter]

If we want to use this functionality in generic helpers to make
sure that all drivers have somewhat sane vblank handling across
modesets/dpms, we need to make it work for all drivers. But some
don't support interrupts and hence also not vblank waits.

Just return early on such drivers.

Note that with pageflips drivers are free to implement them however
they wish to.

Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/drm_irq.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 51ebe9086be9..03fba43ab6be 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -1020,6 +1020,9 @@ void drm_vblank_off(struct drm_device *dev, int crtc)
 	unsigned long irqflags;
 	unsigned int seq;
 
+	if (!dev->irq_enabled)
+		return;
+
 	spin_lock_irqsave(&dev->vbl_lock, irqflags);
 	vblank_disable_and_save(dev, crtc);
 	wake_up(&dev->vblank[crtc].queue);
@@ -1080,6 +1083,9 @@ void drm_vblank_on(struct drm_device *dev, int crtc)
 {
 	unsigned long irqflags;
 
+	if (!dev->irq_enabled)
+		return;
+
 	spin_lock_irqsave(&dev->vbl_lock, irqflags);
 	/* re-enable interrupts if there's are users left */
 	if (atomic_read(&dev->vblank[crtc].refcount) != 0)
-- 
1.8.3.1