Hi all,
some small bug fixes for some small bugs i saw when looking at the current drm vblank handling code.
All patches are rather simple, all compile-tested against drm-next, but only the drm_vblank_off() one (patch 2) tested in "real life" so far.
thanks, -mario
drm_vblank_cleanup() would operate on non-existent dev->vblank data structure, as failure to allocate that data structure is what triggers the error path in the first place.
Signed-off-by: Mario Kleiner mario.kleiner.de@gmail.com Cc: stable@vger.kernel.org --- drivers/gpu/drm/drm_irq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 0de123a..553a58c 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -224,7 +224,7 @@ int drm_vblank_init(struct drm_device *dev, int num_crtcs) return 0;
err: - drm_vblank_cleanup(dev); + dev->num_crtcs = 0; return ret; } EXPORT_SYMBOL(drm_vblank_init);
On Wed, Aug 06, 2014 at 03:22:44AM +0200, Mario Kleiner wrote:
drm_vblank_cleanup() would operate on non-existent dev->vblank data structure, as failure to allocate that data structure is what triggers the error path in the first place.
Signed-off-by: Mario Kleiner mario.kleiner.de@gmail.com Cc: stable@vger.kernel.org
Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com
drivers/gpu/drm/drm_irq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 0de123a..553a58c 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -224,7 +224,7 @@ int drm_vblank_init(struct drm_device *dev, int num_crtcs) return 0;
err:
- drm_vblank_cleanup(dev);
- dev->num_crtcs = 0; return ret;
} EXPORT_SYMBOL(drm_vblank_init); -- 1.9.1
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Move the query for vblank count and time before the vblank_disable_and_save(), because the disable fn will invalidate the vblank timestamps, so all emitted events would carry an invalid zero timestamp instead of the timestamp of the vblank of vblank disable. This could confuse clients.
Signed-off-by: Mario Kleiner mario.kleiner.de@gmail.com Cc: stable@vger.kernel.org --- drivers/gpu/drm/drm_irq.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 553a58c..89e91e3 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -1019,13 +1019,14 @@ void drm_vblank_off(struct drm_device *dev, int crtc) unsigned long irqflags; unsigned int seq;
+ /* Get 'now' vblank ts before it gets cleared by vblank disable */ + seq = drm_vblank_count_and_time(dev, crtc, &now); + spin_lock_irqsave(&dev->vbl_lock, irqflags); vblank_disable_and_save(dev, crtc); wake_up(&dev->vblank[crtc].queue);
/* Send any queued vblank events, lest the natives grow disquiet */ - seq = drm_vblank_count_and_time(dev, crtc, &now); - spin_lock(&dev->event_lock); list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) { if (e->pipe != crtc)
On Wed, Aug 06, 2014 at 03:22:45AM +0200, Mario Kleiner wrote:
Move the query for vblank count and time before the vblank_disable_and_save(), because the disable fn will invalidate the vblank timestamps, so all emitted events would carry an invalid zero timestamp instead of the timestamp of the vblank of vblank disable. This could confuse clients.
Signed-off-by: Mario Kleiner mario.kleiner.de@gmail.com Cc: stable@vger.kernel.org
drivers/gpu/drm/drm_irq.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 553a58c..89e91e3 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -1019,13 +1019,14 @@ void drm_vblank_off(struct drm_device *dev, int crtc) unsigned long irqflags; unsigned int seq;
- /* Get 'now' vblank ts before it gets cleared by vblank disable */
- seq = drm_vblank_count_and_time(dev, crtc, &now);
This will cause us to send out a potentially stale vblank seq/ts. I had a different solution to this (not clearing the timestamps) in my pending vblank series. I have a few more patches on top of that series lined up. Let me send out the full series so we can discuss it if needed...
spin_lock_irqsave(&dev->vbl_lock, irqflags); vblank_disable_and_save(dev, crtc); wake_up(&dev->vblank[crtc].queue);
/* Send any queued vblank events, lest the natives grow disquiet */
- seq = drm_vblank_count_and_time(dev, crtc, &now);
- spin_lock(&dev->event_lock); list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) { if (e->pipe != crtc)
-- 1.9.1
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Calling vblank_disable_fn() will cause that function to no-op if !dev->vblank_disable_allowed for some kms drivers, e.g., on nouveau-kms. This can cause the gpu vblank irq's to not get disabled before freeing the dev->vblank array, so if a vblank irq fires and calls into drm_handle_vblank() after drm_vblank_cleanup() completes, it will cause use-after-free access to dev->vblank array.
Call vblank_disable_and_save unconditionally, so vblank irqs are guaranteed to be off, before we delete the data structures on which they operate.
Signed-off-by: Mario Kleiner mario.kleiner.de@gmail.com Cc: stable@vger.kernel.org --- drivers/gpu/drm/drm_irq.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 89e91e3..22e2bba9 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -164,6 +164,7 @@ static void vblank_disable_fn(unsigned long arg) void drm_vblank_cleanup(struct drm_device *dev) { int crtc; + unsigned long irqflags;
/* Bail if the driver didn't call drm_vblank_init() */ if (dev->num_crtcs == 0) @@ -171,7 +172,9 @@ void drm_vblank_cleanup(struct drm_device *dev)
for (crtc = 0; crtc < dev->num_crtcs; crtc++) { del_timer_sync(&dev->vblank[crtc].disable_timer); - vblank_disable_fn((unsigned long)&dev->vblank[crtc]); + spin_lock_irqsave(&dev->vbl_lock, irqflags); + vblank_disable_and_save(dev, crtc); + spin_unlock_irqrestore(&dev->vbl_lock, irqflags); }
kfree(dev->vblank);
On Wed, Aug 06, 2014 at 03:22:46AM +0200, Mario Kleiner wrote:
Calling vblank_disable_fn() will cause that function to no-op if !dev->vblank_disable_allowed for some kms drivers, e.g., on nouveau-kms. This can cause the gpu vblank irq's to not get disabled before freeing the dev->vblank array, so if a vblank irq fires and calls into drm_handle_vblank() after drm_vblank_cleanup() completes, it will cause use-after-free access to dev->vblank array.
Call vblank_disable_and_save unconditionally, so vblank irqs are guaranteed to be off, before we delete the data structures on which they operate.
Signed-off-by: Mario Kleiner mario.kleiner.de@gmail.com Cc: stable@vger.kernel.org
No idea what games nouveau is playign with that flag, but this patch should be fine at least for drivers that don't do such things.
Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com
drivers/gpu/drm/drm_irq.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 89e91e3..22e2bba9 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -164,6 +164,7 @@ static void vblank_disable_fn(unsigned long arg) void drm_vblank_cleanup(struct drm_device *dev) { int crtc;
unsigned long irqflags;
/* Bail if the driver didn't call drm_vblank_init() */ if (dev->num_crtcs == 0)
@@ -171,7 +172,9 @@ void drm_vblank_cleanup(struct drm_device *dev)
for (crtc = 0; crtc < dev->num_crtcs; crtc++) { del_timer_sync(&dev->vblank[crtc].disable_timer);
vblank_disable_fn((unsigned long)&dev->vblank[crtc]);
spin_lock_irqsave(&dev->vbl_lock, irqflags);vblank_disable_and_save(dev, crtc);spin_unlock_irqrestore(&dev->vbl_lock, irqflags);}
kfree(dev->vblank);
-- 1.9.1
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On Wed, Aug 06, 2014 at 01:51:41PM +0300, Ville Syrjälä wrote:
On Wed, Aug 06, 2014 at 03:22:46AM +0200, Mario Kleiner wrote:
Calling vblank_disable_fn() will cause that function to no-op if !dev->vblank_disable_allowed for some kms drivers, e.g., on nouveau-kms. This can cause the gpu vblank irq's to not get disabled before freeing the dev->vblank array, so if a vblank irq fires and calls into drm_handle_vblank() after drm_vblank_cleanup() completes, it will cause use-after-free access to dev->vblank array.
Call vblank_disable_and_save unconditionally, so vblank irqs are guaranteed to be off, before we delete the data structures on which they operate.
Signed-off-by: Mario Kleiner mario.kleiner.de@gmail.com Cc: stable@vger.kernel.org
Imo cc: stable isn't justified for these patches which fix stuff that normal users don't really see (driver load failure and module reload for kms drivers never tends to happen for normal users).
So I've dropped that and pulled the 2 patches Ville reviewd into my topic/vblank-rework branch for 3.18.
Thanks, Daniel
No idea what games nouveau is playign with that flag, but this patch should be fine at least for drivers that don't do such things.
Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com
drivers/gpu/drm/drm_irq.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 89e91e3..22e2bba9 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -164,6 +164,7 @@ static void vblank_disable_fn(unsigned long arg) void drm_vblank_cleanup(struct drm_device *dev) { int crtc;
unsigned long irqflags;
/* Bail if the driver didn't call drm_vblank_init() */ if (dev->num_crtcs == 0)
@@ -171,7 +172,9 @@ void drm_vblank_cleanup(struct drm_device *dev)
for (crtc = 0; crtc < dev->num_crtcs; crtc++) { del_timer_sync(&dev->vblank[crtc].disable_timer);
vblank_disable_fn((unsigned long)&dev->vblank[crtc]);
spin_lock_irqsave(&dev->vbl_lock, irqflags);vblank_disable_and_save(dev, crtc);spin_unlock_irqrestore(&dev->vbl_lock, irqflags);}
kfree(dev->vblank);
-- 1.9.1
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-- Ville Syrjälä Intel OTC _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel
On 08/06/2014 03:57 PM, Daniel Vetter wrote:
On Wed, Aug 06, 2014 at 01:51:41PM +0300, Ville Syrjälä wrote:
On Wed, Aug 06, 2014 at 03:22:46AM +0200, Mario Kleiner wrote:
Calling vblank_disable_fn() will cause that function to no-op if !dev->vblank_disable_allowed for some kms drivers, e.g., on nouveau-kms. This can cause the gpu vblank irq's to not get disabled before freeing the dev->vblank array, so if a vblank irq fires and calls into drm_handle_vblank() after drm_vblank_cleanup() completes, it will cause use-after-free access to dev->vblank array.
Call vblank_disable_and_save unconditionally, so vblank irqs are guaranteed to be off, before we delete the data structures on which they operate.
Signed-off-by: Mario Kleiner mario.kleiner.de@gmail.com Cc: stable@vger.kernel.org
Imo cc: stable isn't justified for these patches which fix stuff that normal users don't really see (driver load failure and module reload for kms drivers never tends to happen for normal users).
So I've dropped that and pulled the 2 patches Ville reviewd into my topic/vblank-rework branch for 3.18.
Thanks, Daniel
Ok, good with me, thanks. Ville, thanks for the review. I'll review and test your vblank series next week when i have access to suitable machines and enough time. I need to go through this in single-step mode, vblank on/off changes always make me nervous, given how dependent my main application is on this for its timing, so i want to move through it in slow motion.
Btw. wrt to nouveau "No idea what games nouveau is playign with that flag, but this patch should be fine at least for drivers that don't do such things." (Villes comment).
Nouveau currently doesn't support hw vblank counter queries at all. The dev->driver->get_vblank_count() is just hooked up to drm_vblank_count(), so it's a no-op. Therefore nouveau can't allow disabling of vblank irq during "normal" operation as it would lose all vblank counts during the off period. That's why it leaves dev->vblank_disable_allowed = false;
Pre NV-50 apparently doesn't have any hw vblank counter register, but NV50+ seems to have one. I'll probably give implementing this a try for 3.18 if nobody else does.
I'm not sure about all the new embedded drivers, if they have hw vblank counters?
thanks, -mario
No idea what games nouveau is playign with that flag, but this patch should be fine at least for drivers that don't do such things.
Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com
drivers/gpu/drm/drm_irq.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 89e91e3..22e2bba9 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -164,6 +164,7 @@ static void vblank_disable_fn(unsigned long arg) void drm_vblank_cleanup(struct drm_device *dev) { int crtc;
unsigned long irqflags;
/* Bail if the driver didn't call drm_vblank_init() */ if (dev->num_crtcs == 0)
@@ -171,7 +172,9 @@ void drm_vblank_cleanup(struct drm_device *dev)
for (crtc = 0; crtc < dev->num_crtcs; crtc++) { del_timer_sync(&dev->vblank[crtc].disable_timer);
vblank_disable_fn((unsigned long)&dev->vblank[crtc]);
spin_lock_irqsave(&dev->vbl_lock, irqflags);vblank_disable_and_save(dev, crtc);spin_unlock_irqrestore(&dev->vbl_lock, irqflags);}
kfree(dev->vblank);
-- 1.9.1
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-- Ville Syrjälä Intel OTC _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel
On Thu, Aug 7, 2014 at 2:50 AM, Mario Kleiner mario.kleiner.de@gmail.com wrote:
I'm not sure about all the new embedded drivers, if they have hw vblank counters?
Quick grep says a lot don't have it or at least not implemented - they use drm_vblank_count. Thinking about this, should we use that as a signal to also set dev->vblnka_disable_allowed = false in drm_vblank_init? -Daniel
On 08/07/2014 08:50 AM, Daniel Vetter wrote:
On Thu, Aug 7, 2014 at 2:50 AM, Mario Kleiner mario.kleiner.de@gmail.com wrote:
I'm not sure about all the new embedded drivers, if they have hw vblank counters?
Quick grep says a lot don't have it or at least not implemented - they use drm_vblank_count. Thinking about this, should we use that as a signal to also set dev->vblnka_disable_allowed = false in drm_vblank_init? -Daniel
dev->vblank_disable_allowed = false; is already the default set in drm_vblank_init(). I think it was the idea of that flag that drivers which support a somewhat correct vblank dis/enable (= have useable hw vblank counters) opt-in to the vblank disable after some idle time by setting it to true.
The strange thing is that unconditional dev->vblank_disable_allowed = true in drm_vblank_post_modeset()? It's there since the first introduction of the flag.
The i915, gma500, armada and exynos drivers explicitely set the flag to true to opt-in to the auto vblank disable. radeon gets it implicitely set by calling the vblank_post_modeset function. Tegra also gets it via the post_modeset, and nouveau on old cards with nv04 display engine.
armada, exynos and tegra don't have proper hw vblank counter queries, but opt-in, so those will lose vblank counts whenever vblank irqs get turned off.
It's a bit all over the place. -mario
On Thu, Aug 7, 2014 at 2:50 AM, Mario Kleiner mario.kleiner.de@gmail.com wrote:
Ok, good with me, thanks. Ville, thanks for the review. I'll review and test your vblank series next week when i have access to suitable machines and enough time. I need to go through this in single-step mode, vblank on/off changes always make me nervous, given how dependent my main application is on this for its timing, so i want to move through it in slow motion.
btw I've pulled in your patches and the one's from Ville that I think are sane into a topic branch, in case that helps:
http://cgit.freedesktop.org/drm-intel/log/?h=topic/vblank-rework
Cheers, Daniel
On Wed, Aug 6, 2014 at 3:22 AM, Mario Kleiner mario.kleiner.de@gmail.com wrote:
some small bug fixes for some small bugs i saw when looking at the current drm vblank handling code.
All patches are rather simple, all compile-tested against drm-next, but only the drm_vblank_off() one (patch 2) tested in "real life" so far.
Ville has an older patch series touching the same code and afaict fixing some of the same bugs. Unfortunately it's not in yet. Have you looked at that one? -Daniel
dri-devel@lists.freedesktop.org
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Ville Syrjälä