| Message ID | 1393009415-27651-5-git-send-email-ville.syrjala@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 21 Feb 2014 21:03:34 +0200 ville.syrjala@linux.intel.com wrote: > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > If someone holds a vblank reference across the modeset, and after/during > the modeset someone tries to grab a vblank reference, the current code > won't re-enable the vblank interrupts. That's not good, so instead allow > the driver to choose whether drm_vblank_get() should always enable the > interrupts regardless of the refcount. > > Combined with the drm_vblank_off/drm_vblank_on reject mechanism, this > can also be used to allow drivers to use vblank interrupts during > modeset, whether or not someone is currently holding a vblank reference. > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > --- > drivers/gpu/drm/drm_irq.c | 3 ++- > include/drm/drmP.h | 6 ++++++ > 2 files changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c > index 6e5d820..d613b6f 100644 > --- a/drivers/gpu/drm/drm_irq.c > +++ b/drivers/gpu/drm/drm_irq.c > @@ -897,7 +897,8 @@ int drm_vblank_get(struct drm_device *dev, int crtc) > } > > /* Going from 0->1 means we have to enable interrupts again */ > - if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1) { > + if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1 || > + dev->vblank_always_enable_on_get) { > spin_lock(&dev->vblank_time_lock); > if (!dev->vblank[crtc].enabled) { > /* Enable vblank irqs under vblank_time_lock protection. > diff --git a/include/drm/drmP.h b/include/drm/drmP.h > index ee40483..3eca0ee 100644 > --- a/include/drm/drmP.h > +++ b/include/drm/drmP.h > @@ -1156,6 +1156,12 @@ struct drm_device { > */ > bool vblank_disable_allowed; > > + /* > + * Should a non-rejected drm_vblank_get() always enable the > + * vblank interrupt regardless of the current refcount? > + */ > + bool vblank_always_enable_on_get; > + > /* array of size num_crtcs */ > struct drm_vblank_crtc *vblank; > This seems like the sort of thing it would be good to have a test for... I'm surprised we haven't hit it yet. But in looking at the code I don't see where we'd re-enable things properly in this situation, so I guess it's a real bug. Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
On Fri, Feb 21, 2014 at 09:03:34PM +0200, ville.syrjala@linux.intel.com wrote: > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > If someone holds a vblank reference across the modeset, and after/during > the modeset someone tries to grab a vblank reference, the current code > won't re-enable the vblank interrupts. That's not good, so instead allow > the driver to choose whether drm_vblank_get() should always enable the > interrupts regardless of the refcount. > > Combined with the drm_vblank_off/drm_vblank_on reject mechanism, this > can also be used to allow drivers to use vblank interrupts during > modeset, whether or not someone is currently holding a vblank reference. > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > --- > drivers/gpu/drm/drm_irq.c | 3 ++- > include/drm/drmP.h | 6 ++++++ > 2 files changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c > index 6e5d820..d613b6f 100644 > --- a/drivers/gpu/drm/drm_irq.c > +++ b/drivers/gpu/drm/drm_irq.c > @@ -897,7 +897,8 @@ int drm_vblank_get(struct drm_device *dev, int crtc) > } > > /* Going from 0->1 means we have to enable interrupts again */ > - if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1) { > + if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1 || > + dev->vblank_always_enable_on_get) { > spin_lock(&dev->vblank_time_lock); > if (!dev->vblank[crtc].enabled) { > /* Enable vblank irqs under vblank_time_lock protection. > diff --git a/include/drm/drmP.h b/include/drm/drmP.h > index ee40483..3eca0ee 100644 > --- a/include/drm/drmP.h > +++ b/include/drm/drmP.h > @@ -1156,6 +1156,12 @@ struct drm_device { > */ > bool vblank_disable_allowed; > > + /* > + * Should a non-rejected drm_vblank_get() always enable the > + * vblank interrupt regardless of the current refcount? > + */ > + bool vblank_always_enable_on_get; Nack for this hack. Why can't drm_vblank_on not just re-enable the vblank interrupt if we still have a vblank reference? -Daniel > + > /* array of size num_crtcs */ > struct drm_vblank_crtc *vblank; > > -- > 1.8.3.2 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel
On Tue, Mar 04, 2014 at 10:16:02AM +0100, Daniel Vetter wrote: > On Fri, Feb 21, 2014 at 09:03:34PM +0200, ville.syrjala@linux.intel.com wrote: > > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > > > If someone holds a vblank reference across the modeset, and after/during > > the modeset someone tries to grab a vblank reference, the current code > > won't re-enable the vblank interrupts. That's not good, so instead allow > > the driver to choose whether drm_vblank_get() should always enable the > > interrupts regardless of the refcount. > > > > Combined with the drm_vblank_off/drm_vblank_on reject mechanism, this > > can also be used to allow drivers to use vblank interrupts during > > modeset, whether or not someone is currently holding a vblank reference. > > > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > > --- > > drivers/gpu/drm/drm_irq.c | 3 ++- > > include/drm/drmP.h | 6 ++++++ > > 2 files changed, 8 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c > > index 6e5d820..d613b6f 100644 > > --- a/drivers/gpu/drm/drm_irq.c > > +++ b/drivers/gpu/drm/drm_irq.c > > @@ -897,7 +897,8 @@ int drm_vblank_get(struct drm_device *dev, int crtc) > > } > > > > /* Going from 0->1 means we have to enable interrupts again */ > > - if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1) { > > + if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1 || > > + dev->vblank_always_enable_on_get) { > > spin_lock(&dev->vblank_time_lock); > > if (!dev->vblank[crtc].enabled) { > > /* Enable vblank irqs under vblank_time_lock protection. > > diff --git a/include/drm/drmP.h b/include/drm/drmP.h > > index ee40483..3eca0ee 100644 > > --- a/include/drm/drmP.h > > +++ b/include/drm/drmP.h > > @@ -1156,6 +1156,12 @@ struct drm_device { > > */ > > bool vblank_disable_allowed; > > > > + /* > > + * Should a non-rejected drm_vblank_get() always enable the > > + * vblank interrupt regardless of the current refcount? > > + */ > > + bool vblank_always_enable_on_get; > > Nack for this hack. Why can't drm_vblank_on not just re-enable the vblank > interrupt if we still have a vblank reference? Hmm. Yeah that seems like a nicer way to go about it.
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 6e5d820..d613b6f 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -897,7 +897,8 @@ int drm_vblank_get(struct drm_device *dev, int crtc) } /* Going from 0->1 means we have to enable interrupts again */ - if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1) { + if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1 || + dev->vblank_always_enable_on_get) { spin_lock(&dev->vblank_time_lock); if (!dev->vblank[crtc].enabled) { /* Enable vblank irqs under vblank_time_lock protection. diff --git a/include/drm/drmP.h b/include/drm/drmP.h index ee40483..3eca0ee 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -1156,6 +1156,12 @@ struct drm_device { */ bool vblank_disable_allowed; + /* + * Should a non-rejected drm_vblank_get() always enable the + * vblank interrupt regardless of the current refcount? + */ + bool vblank_always_enable_on_get; + /* array of size num_crtcs */ struct drm_vblank_crtc *vblank;