Apparently pre-nv50 pageflip events happen before the actual vblank
period. Therefore that functionality got semi-disabled in
commit af4870e406126b7ac0ae7c7ce5751f25ebe60f28
Author: Mario Kleiner <mario.kleiner...@gmail.com>
Date: Tue May 13 00:42:08 2014 +0200
drm/nouveau/kms/nv04-nv40: fix pageflip events via special case.
Unfortunately that hack got uprooted in
commit cc1ef118fc099295ae6aabbacc8af94d8d8885eb
Author: Thierry Reding <tred...@nvidia.com>
Date: Wed Aug 12 17:00:31 2015 +0200
drm/irq: Make pipe unsigned and name consistent
Trigering a warning when trying to sample the vblank timestamp for a
non-existing pipe. There's a few ways to fix this:
- Open-code the old behaviour, which just enshrines this slight
breakage of the userspace ABI.
- Revert Mario's commit and again inflict broken timestamps, again not
pretty.
- Fix this for real by delaying the pageflip TS until the next vblank
interrupt, thereby making it accurate.
This patch implements the third option. Since having a page flip
interrupt that happens when the pageflip gets armed and not when it
completes in the next vblank seems to be fairly common (older i915 hw
works very similarly) create a new helper to arm vblank events for
such drivers.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=106431
Cc: Thierry Reding <tred...@nvidia.com>
Cc: Mario Kleiner <mario.kleiner...@gmail.com>
Cc: Ben Skeggs <bske...@redhat.com>
Cc: Ilia Mirkin <imir...@alum.mit.edu>
Signed-off-by: Daniel Vetter <daniel.vet...@intel.com>
---
Note that due to lack of hw this is completely untested. But I think
it's the right way to fix this.
-Daniel
---
drivers/gpu/drm/drm_irq.c | 56 ++++++++++++++++++++++++++++++-
drivers/gpu/drm/nouveau/nouveau_display.c | 16 ++++-----
include/drm/drmP.h | 4 +++
3 files changed, 66 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 46dbc34b81ba..b3e1f58666a6 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -972,7 +972,8 @@ static void send_vblank_event(struct drm_device *dev,
struct drm_pending_vblank_event *e,
unsigned long seq, struct timeval *now)
{
- WARN_ON_SMP(!spin_is_locked(&dev->event_lock));
+ assert_spin_locked(&dev->event_lock);
+
e->event.sequence = seq;
e->event.tv_sec = now->tv_sec;
e->event.tv_usec = now->tv_usec;
@@ -985,6 +986,59 @@ static void send_vblank_event(struct drm_device *dev,
}
/**
+ * drm_arm_vblank_event - arm vblanke event after pageflip
+ * @dev: DRM device
+ * @pipe: CRTC index
+ * @e: the event to prepare to send
+ *
+ * A lot of drivers need to generate vblank events for the very next vblank
+ * interrupt. For example when the page flip interrupt happens when the page
+ * flip gets armed, but not when it actually executes within the next vblank
+ * period. This helper function implements exactly the required vblank arming
+ * behaviour.
+ *
+ * Caller must hold event lock. Caller must also hold a vblank reference for
the
+ * event @e, which will be dropped when the next vblank arrives.
+ *
+ * This is the legacy version of drm_crtc_arm_vblank_event().
+ */
+void drm_arm_vblank_event(struct drm_device *dev, unsigned int pipe,
+ struct drm_pending_vblank_event *e)
+{
+ struct timeval now;
+ unsigned int seq;
+
+ assert_spin_locked(&dev->event_lock);
+
+ e->pipe = pipe;
+ list_add_tail(&e->base.link, &dev->vblank_event_list);
+}
+EXPORT_SYMBOL(drm_arm_vblank_event);
+
+/**
+ * drm_arm_vblank_event - arm vblanke event after pageflip
+ * @crtc: the source CRTC of the vblank event
+ * @e: the event to send
+ *
+ * A lot of drivers need to generate vblank events for the very next vblank
+ * interrupt. For example when the page flip interrupt happens when the page
+ * flip gets armed, but not when it actually executes within the next vblank
+ * period. This helper function implements exactly the required vblank arming
+ * behaviour.
+ *
+ * Caller must hold event lock. Caller must also hold a vblank reference for
the
+ * event @e, which will be dropped when the next vblank arrives.
+ *
+ * This is the native KMS version of drm_send_vblank_event().
+ */
+void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
+ struct drm_pending_vblank_event *e)
+{
+ drm_arm_vblank_event(crtc->dev, drm_crtc_index(crtc), e);
+}
+EXPORT_SYMBOL(drm_crtc_arm_vblank_event);
+
+/**
* drm_send_vblank_event - helper to send vblank event after pageflip
* @dev: DRM device
* @pipe: CRTC index
diff --git a/drivers/gpu/drm/nouveau/nouveau_display.c
b/drivers/gpu/drm/nouveau/nouveau_display.c
index 184445d4abbf..041e5f84538c 100644
--- a/drivers/gpu/drm/nouveau/nouveau_display.c
+++ b/drivers/gpu/drm/nouveau/nouveau_display.c
@@ -826,7 +826,6 @@ nouveau_finish_page_flip(struct nouveau_channel *chan,
struct drm_device *dev = drm->dev;
struct nouveau_page_flip_state *s;
unsigned long flags;
- int crtcid = -1;
spin_lock_irqsave(&dev->event_lock, flags);
@@ -838,16 +837,15 @@ nouveau_finish_page_flip(struct nouveau_channel *chan,
s = list_first_entry(&fctx->flip, struct nouveau_page_flip_state, head);
if (s->event) {
- /* Vblank timestamps/counts are only correct on >= NV-50 */
- if (drm->device.info.family >= NV_DEVICE_INFO_V0_TESLA)
- crtcid = s->crtc;
-
- drm_send_vblank_event(dev, crtcid, s->event);
+ if (drm->device.info.family < NV_DEVICE_INFO_V0_TESLA) {
+ drm_arm_vblank_event(dev, s->crtc, s->event);
+ } else {
+ drm_send_vblank_event(dev, s->crtc, s->event);
+ /* Give up ownership of vblank for page-flipped crtc */
+ drm_vblank_put(dev, s->crtc);
+ }
}
- /* Give up ownership of vblank for page-flipped crtc */
- drm_vblank_put(dev, s->crtc);
-
list_del(&s->head);
if (ps)
*ps = *s;
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index eb513341b6ee..4c91ac419d5d 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -948,6 +948,10 @@ extern void drm_send_vblank_event(struct drm_device *dev,
unsigned int pipe,
struct drm_pending_vblank_event *e);
extern void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
struct drm_pending_vblank_event *e);
+void drm_send_vblank_event(struct drm_device *dev, unsigned int pipe,
+ struct drm_pending_vblank_event *e);
+void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
+ struct drm_pending_vblank_event *e);
extern bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
extern bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
extern int drm_vblank_get(struct drm_device *dev, unsigned int pipe);
--
2.5.1
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