VBLANK interrupts can be disabled immediately or with a delay, where the
latter is the default. The former option can be selected by setting
get_vblank_timestamp, and enabling vblank_disable_immediate in struct
drm_device.
The setup is only evaluated once when DRM initializes VBLANKs. Evaluating
the settings on each use of vblank_disable_immediate will allow for easy
integration of CRTC VBLANK functions.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
drivers/gpu/drm/drm_vblank.c | 31 ++++++++++++++-----------------
1 file changed, 14 insertions(+), 17 deletions(-)
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index 3f1dd54cc8bb..abb085c67d82 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -481,19 +481,6 @@ int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs)
DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
- /* Driver specific high-precision vblank timestamping supported? */
- if (dev->driver->get_vblank_timestamp)
- DRM_INFO("Driver supports precise vblank timestamp query.\n");
- else
- DRM_INFO("No driver support for vblank timestamp query.\n");
-
- /* Must have precise timestamping for reliable vblank instant disable */
- if (dev->vblank_disable_immediate && !dev->driver->get_vblank_timestamp) {
- dev->vblank_disable_immediate = false;
- DRM_INFO("Setting vblank_disable_immediate to false because "
- "get_vblank_timestamp == NULL\n");
- }
-
return 0;
err:
@@ -1070,6 +1057,15 @@ int drm_crtc_vblank_get(struct drm_crtc *crtc)
}
EXPORT_SYMBOL(drm_crtc_vblank_get);
+static bool __vblank_disable_immediate(struct drm_device *dev, unsigned int pipe)
+{
+ if (!dev->vblank_disable_immediate)
+ return false;
+ if (!dev->driver->get_vblank_timestamp)
+ return false;
+ return true;
+}
+
static void drm_vblank_put(struct drm_device *dev, unsigned int pipe)
{
struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
@@ -1086,7 +1082,7 @@ static void drm_vblank_put(struct drm_device *dev, unsigned int pipe)
return;
else if (drm_vblank_offdelay < 0)
vblank_disable_fn(&vblank->disable_timer);
- else if (!dev->vblank_disable_immediate)
+ else if (__vblank_disable_immediate(dev, pipe))
mod_timer(&vblank->disable_timer,
jiffies + ((drm_vblank_offdelay * HZ)/1000));
}
@@ -1663,7 +1659,7 @@ int drm_wait_vblank_ioctl(struct drm_device *dev, void *data,
/* If the counter is currently enabled and accurate, short-circuit
* queries to return the cached timestamp of the last vblank.
*/
- if (dev->vblank_disable_immediate &&
+ if (__vblank_disable_immediate(dev, pipe) &&
drm_wait_vblank_is_query(vblwait) &&
READ_ONCE(vblank->enabled)) {
drm_wait_vblank_reply(dev, pipe, &vblwait->reply);
@@ -1820,7 +1816,7 @@ bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe)
* been signaled. The disable has to be last (after
* drm_handle_vblank_events) so that the timestamp is always accurate.
*/
- disable_irq = (dev->vblank_disable_immediate &&
+ disable_irq = (__vblank_disable_immediate(dev, pipe) &&
drm_vblank_offdelay > 0 &&
!atomic_read(&vblank->refcount));
@@ -1893,7 +1889,8 @@ int drm_crtc_get_sequence_ioctl(struct drm_device *dev, void *data,
pipe = drm_crtc_index(crtc);
vblank = &dev->vblank[pipe];
- vblank_enabled = dev->vblank_disable_immediate && READ_ONCE(vblank->enabled);
+ vblank_enabled = __vblank_disable_immediate(dev, pipe) &&
+ READ_ONCE(vblank->enabled);
if (!vblank_enabled) {
ret = drm_crtc_vblank_get(crtc);
--
2.24.1
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