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@gmail.com Cc: stable@vger.kernel.org # 3.18+ Cc: michel@daenzer.net Cc: vbabka@suse.cz Cc: ville.syrjala@linux.intel.com Cc: daniel.vetter@ffwll.ch Cc: dri-devel@lists.freedesktop.org Cc: alexander.deucher@amd.com Cc: christian.koenig@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); }