drm_vblank_offdelay can have three different types of values:
< 0 is to be always treated the same as dev->vblank_disable_immediate
= 0 is to be treated as "never disable vblanks"
> 0 is to be treated as disable immediate if kms driver wants it
that way via dev->vblank_disable_immediate. Otherwise it is
a disable timeout in msecs.
This got broken in Linux 3.18+ for the implementation of
drm_vblank_on. If the user specified a value of zero which should
always reenable vblank irqs in this function, a kms driver could
override the users choice by setting vblank_disable_immediate
to true. This patch fixes the regression and keeps the user in
control.
Signed-off-by: Mario Kleiner <mario.kleiner.de at gmail.com>
Cc: <stable at vger.kernel.org> # 3.18+
Cc: michel at daenzer.net
Cc: vbabka at suse.cz
Cc: ville.syrjala at linux.intel.com
Cc: daniel.vetter at ffwll.ch
Cc: dri-devel at lists.freedesktop.org
Cc: alexander.deucher at amd.com
Cc: christian.koenig at amd.com
---
drivers/gpu/drm/drm_irq.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 5c27ad3..fb17c45 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -1492,8 +1492,8 @@ void drm_vblank_on(struct drm_device *dev, unsigned int
pipe)
* re-enable interrupts if there are users left, or the
* user wishes vblank interrupts to be enabled all the time.
*/
- if (atomic_read(&vblank->refcount) != 0 ||
- (!dev->vblank_disable_immediate && drm_vblank_offdelay == 0))
+ if (atomic_read(&vblank->refcount) != 0 || drm_vblank_offdelay == 0 ||
+ (!dev->vblank_disable_immediate && drm_vblank_offdelay > 0))
WARN_ON(drm_vblank_enable(dev, pipe));
spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
}
--
1.9.1
