From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
If someone holds a vblank reference across the modeset, and after/during
the modeset someone tries to grab a vblank reference, the current code
won't re-enable the vblank interrupts. That's not good, so instead allow
the driver to choose whether drm_vblank_get() should always enable the
interrupts regardless of the refcount.
Combined with the drm_vblank_off/drm_vblank_on reject mechanism, this
can also be used to allow drivers to use vblank interrupts during
modeset, whether or not someone is currently holding a vblank reference.
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_irq.c | 3 ++-
include/drm/drmP.h | 6 ++++++
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 6e5d820..d613b6f 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -897,7 +897,8 @@ int drm_vblank_get(struct drm_device *dev, int crtc)
}
/* Going from 0->1 means we have to enable interrupts again */
- if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1) {
+ if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1 ||
+ dev->vblank_always_enable_on_get) {
spin_lock(&dev->vblank_time_lock);
if (!dev->vblank[crtc].enabled) {
/* Enable vblank irqs under vblank_time_lock protection.
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index ee40483..3eca0ee 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1156,6 +1156,12 @@ struct drm_device {
*/
bool vblank_disable_allowed;
+ /*
+ * Should a non-rejected drm_vblank_get() always enable the
+ * vblank interrupt regardless of the current refcount?
+ */
+ bool vblank_always_enable_on_get;
+
/* array of size num_crtcs */
struct drm_vblank_crtc *vblank;
--
1.8.3.2
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