[PATCH 1/4] drm: Really never disable vblank irqs for offdelay==0

[Daniel Vetter]

With the new support for immediate vblank disabling we always disabled
the vblank interrupt right away, irrespective of the vblank offdelay
setting.

But being able to let vblanks run forever is fairly useful for
debugging, so restore that behaviour.

Suggested-by: Mario Kleiner <mario.kleiner.de at gmail.com>
Cc: Mario Kleiner <mario.kleiner.de at gmail.com>
Cc: Matt Roper <matthew.d.roper at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 drivers/gpu/drm/drm_irq.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index a75da075927c..6eb015020af2 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -1024,9 +1024,11 @@ void drm_vblank_put(struct drm_device *dev, int crtc)
 
 	/* Last user schedules interrupt disable */
 	if (atomic_dec_and_test(&vblank->refcount)) {
-		if (dev->vblank_disable_immediate || drm_vblank_offdelay < 0)
+		if (drm_vblank_offdelay == 0)
+			return;
+		else if (dev->vblank_disable_immediate || drm_vblank_offdelay < 0)
 			vblank_disable_fn((unsigned long)vblank);
-		else if (drm_vblank_offdelay > 0)
+		else
 			mod_timer(&vblank->disable_timer,
 				  jiffies + ((drm_vblank_offdelay * HZ)/1000));
 	}
-- 
1.9.3