diff mbox

drm/nouveau: Fix pre-nv50 pageflip events (v4)

Message ID 1447173451-27890-1-git-send-email-thierry.reding@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Thierry Reding Nov. 10, 2015, 4:37 p.m. UTC
From: Daniel Vetter <daniel.vetter@ffwll.ch>

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>
Cc: 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>
---
 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(-)

Comments

Thierry Reding Nov. 10, 2015, 4:41 p.m. UTC | #1
On Tue, Nov 10, 2015 at 05:37:31PM +0100, Thierry Reding wrote:
> From: Daniel Vetter <daniel.vetter@ffwll.ch>
> 
> 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>
> Cc: 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>
> ---
>  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(-)

Hi Dave,

It'd be great if you could queue this up for fixes, since it gets rid of
a WARN_ON() that is triggered on a number of cards in v4.3. I realize
that this is a tad big for stable, but it's the right way to fix this.
If you'd prefer something smaller, I think we can fix the regression
using a one-line band-aid and then apply this one on top for v4.4.

Thierry
poma Dec. 15, 2015, 11:11 a.m. UTC | #2
On 10.11.2015 17:41, Thierry Reding wrote:
> On Tue, Nov 10, 2015 at 05:37:31PM +0100, Thierry Reding wrote:
>> From: Daniel Vetter <daniel.vetter@ffwll.ch>
>>
>> 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>
>> Cc: 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>
>> ---
>>  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(-)
> 
> Hi Dave,
> 
> It'd be great if you could queue this up for fixes, since it gets rid of
> a WARN_ON() that is triggered on a number of cards in v4.3. I realize
> that this is a tad big for stable, but it's the right way to fix this.
> If you'd prefer something smaller, I think we can fix the regression
> using a one-line band-aid and then apply this one on top for v4.4.
> 
> Thierry
> 


Apparently not reached @stable (stable:	4.3.3 2015-12-15),
so here's one more time.
Emil Velikov Dec. 15, 2015, 11:21 a.m. UTC | #3
On 15 December 2015 at 11:11, poma <pomidorabelisima@gmail.com> wrote:

>
> Apparently not reached @stable (stable: 4.3.3 2015-12-15),
> so here's one more time.
>
It has reached 4.4-rcX and will get picked by the stable maintainer
(Greg?) in due time. Meanwhile you can ask your distro maintainers to
apply it locally until we get an official release that includes it.

-Emil
poma Dec. 15, 2015, 3:01 p.m. UTC | #4
On 15.12.2015 12:21, Emil Velikov wrote:
> On 15 December 2015 at 11:11, poma <pomidorabelisima@gmail.com> wrote:
> 
>>
>> Apparently not reached @stable (stable: 4.3.3 2015-12-15),
>> so here's one more time.
>>
> It has reached 4.4-rcX and will get picked by the stable maintainer
> (Greg?) in due time. Meanwhile you can ask your distro maintainers to
> apply it locally until we get an official release that includes it.
> 
> -Emil
> 

It is all but unknown ;)
https://bugzilla.redhat.com/show_bug.cgi?id=1281368

Emil, the point is - if it has -not- reached stable@vger.kernel.org, how can it be applied, in the first place.

Aye
Emil Velikov Dec. 15, 2015, 3:17 p.m. UTC | #5
On 15 December 2015 at 15:01, poma <pomidorabelisima@gmail.com> wrote:
> On 15.12.2015 12:21, Emil Velikov wrote:
>> On 15 December 2015 at 11:11, poma <pomidorabelisima@gmail.com> wrote:
>>
>>>
>>> Apparently not reached @stable (stable: 4.3.3 2015-12-15),
>>> so here's one more time.
>>>
>> It has reached 4.4-rcX and will get picked by the stable maintainer
>> (Greg?) in due time. Meanwhile you can ask your distro maintainers to
>> apply it locally until we get an official release that includes it.
>>
>> -Emil
>>
>
> It is all but unknown ;)
> https://bugzilla.redhat.com/show_bug.cgi?id=1281368
>
> Emil, the point is - if it has -not- reached stable@vger.kernel.org, how can it be applied, in the first place.
>
The same way many others do ? I'd imagine there is a tool/script which
parses through the development tree, which would explain why (many?)
people explicitly suppress git from sending an email yet things still
work. There is extra information in the documentation [1] if you're
interested.

-Emil
[1] https://www.kernel.org/doc/Documentation/stable_kernel_rules.txt
Greg KH Dec. 15, 2015, 5:04 p.m. UTC | #6
On Tue, Dec 15, 2015 at 03:17:21PM +0000, Emil Velikov wrote:
> On 15 December 2015 at 15:01, poma <pomidorabelisima@gmail.com> wrote:
> > On 15.12.2015 12:21, Emil Velikov wrote:
> >> On 15 December 2015 at 11:11, poma <pomidorabelisima@gmail.com> wrote:
> >>
> >>>
> >>> Apparently not reached @stable (stable: 4.3.3 2015-12-15),
> >>> so here's one more time.
> >>>
> >> It has reached 4.4-rcX and will get picked by the stable maintainer
> >> (Greg?) in due time. Meanwhile you can ask your distro maintainers to
> >> apply it locally until we get an official release that includes it.
> >>
> >> -Emil
> >>
> >
> > It is all but unknown ;)
> > https://bugzilla.redhat.com/show_bug.cgi?id=1281368
> >
> > Emil, the point is - if it has -not- reached stable@vger.kernel.org, how can it be applied, in the first place.
> >
> The same way many others do ? I'd imagine there is a tool/script which
> parses through the development tree, which would explain why (many?)
> people explicitly suppress git from sending an email yet things still
> work. There is extra information in the documentation [1] if you're
> interested.

Yes, this is in the queue, along with 276 other patches that I need to
apply as well.  The backlog is large this time of year, sorry.

greg k-h
diff mbox

Patch

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);