From 424f582d0ec7f206dcc59d34c9a2fa1c8087a8aa Mon Sep 17 00:00:00 2001

From: Daniel Vetter <daniel.vetter@ffwll.ch>

Date: Tue, 10 Nov 2015 17:37:31 +0100

Subject: [PATCH] drm/nouveau: Fix pre-nv50 pageflip events (v4)

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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.de@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 <treding@nvidia.com>

Date:   Wed Aug 12 17:00:31 2015 +0200

    drm/irq: Make pipe unsigned and name consistent

Triggering 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.

v2 (Mario Kleiner):

- Fix function prototypes in drmP.h

- Add missing vblank_put() for pageflip completion without

  pageflip event.

- Initialize sequence number for queued pageflip event to avoid

  trouble in drm_handle_vblank_events().

- Remove dead code and spelling fix.

v3 (Mario Kleiner):

- Add a signed-off-by and cc stable tag per Ilja's advice.

v4 (Thierry Reding):

- Fix kerneldoc typo, discovered by Michel Dänzer

- Rearrange tags and changelog

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=106431

Cc: Thierry Reding <treding@nvidia.com>

Cc: Mario Kleiner <mario.kleiner.de@gmail.com>

Acked-by: Ben Skeggs <bskeggs@redhat.com>

Cc: Ilia Mirkin <imirkin@alum.mit.edu>

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Reviewed-by: Mario Kleiner <mario.kleiner.de@gmail.com>

Cc: stable@vger.kernel.org # v4.3

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>

Signed-off-by: Thierry Reding <treding@nvidia.com>

Signed-off-by: Dave Airlie <airlied@redhat.com>

---

 drivers/gpu/drm/drm_irq.c                 | 54 ++++++++++++++++++++++++++++++-

 drivers/gpu/drm/nouveau/nouveau_display.c | 19 ++++++-----

 include/drm/drmP.h                        |  4 +++

 3 files changed, 68 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c

index 22d207e211e7..c5f20e41dcc6 100644

--- a/drivers/gpu/drm/drm_irq.c

+++ b/drivers/gpu/drm/drm_irq.c

@@ -944,7 +944,8 @@ 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;

@@ -957,6 +958,57 @@ static void send_vblank_event(struct drm_device *dev,

 }

 /**

+ * drm_arm_vblank_event - arm vblank 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)

+{

+	assert_spin_locked(&dev->event_lock);

+

+	e->pipe = pipe;

+	e->event.sequence = drm_vblank_count(dev, pipe);

+	list_add_tail(&e->base.link, &dev->vblank_event_list);

+}

+EXPORT_SYMBOL(drm_arm_vblank_event);

+

+/**

+ * drm_crtc_arm_vblank_event - arm vblank 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_arm_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 e905c00acf1a..54183bcca48f 100644

--- a/drivers/gpu/drm/nouveau/nouveau_display.c

+++ b/drivers/gpu/drm/nouveau/nouveau_display.c

@@ -827,7 +827,6 @@ 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);

@@ -839,15 +838,19 @@ 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;

+		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);

-		drm_send_vblank_event(dev, crtcid, s->event);

+			/* Give up ownership of vblank for page-flipped crtc */

+			drm_vblank_put(dev, s->crtc);

+		}

+	}

+	else {

+		/* 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)

diff --git a/include/drm/drmP.h b/include/drm/drmP.h

index 8b5ce7c5d9bb..c98f01046bd0 100644

--- a/include/drm/drmP.h

+++ b/include/drm/drmP.h

@@ -932,6 +932,10 @@ 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);

+extern void drm_arm_vblank_event(struct drm_device *dev, unsigned int pipe,

+				 struct drm_pending_vblank_event *e);

+extern void drm_crtc_arm_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);

-- 

2.5.0