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[PATCH v9 11/15] drm/atomic-helper: Set fence deadline for vblank

Rob Clark posted 15 patches 3 years, 1 month ago
There is a newer version of this series
[PATCH v9 11/15] drm/atomic-helper: Set fence deadline for vblank
Posted by Rob Clark 3 years, 1 month ago 
From: Rob Clark <robdclark@chromium.org>

For an atomic commit updating a single CRTC (ie. a pageflip) calculate
the next vblank time, and inform the fence(s) of that deadline.

v2: Comment typo fix (danvet)

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/gpu/drm/drm_atomic_helper.c | 36 +++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index d579fd8f7cb8..d8ee98ce2fc5 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1511,6 +1511,40 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_atomic_helper_commit_modeset_enables);
 
+/*
+ * For atomic updates which touch just a single CRTC, calculate the time of the
+ * next vblank, and inform all the fences of the deadline.
+ */
+static void set_fence_deadline(struct drm_device *dev,
+			       struct drm_atomic_state *state)
+{
+	struct drm_crtc *crtc, *wait_crtc = NULL;
+	struct drm_crtc_state *new_crtc_state;
+	struct drm_plane *plane;
+	struct drm_plane_state *new_plane_state;
+	ktime_t vbltime;
+	int i;
+
+	for_each_new_crtc_in_state (state, crtc, new_crtc_state, i) {
+		if (wait_crtc)
+			return;
+		wait_crtc = crtc;
+	}
+
+	/* If no CRTCs updated, then nothing to do: */
+	if (!wait_crtc)
+		return;
+
+	if (drm_crtc_next_vblank_start(wait_crtc, &vbltime))
+		return;
+
+	for_each_new_plane_in_state (state, plane, new_plane_state, i) {
+		if (!new_plane_state->fence)
+			continue;
+		dma_fence_set_deadline(new_plane_state->fence, vbltime);
+	}
+}
+
 /**
  * drm_atomic_helper_wait_for_fences - wait for fences stashed in plane state
  * @dev: DRM device
@@ -1540,6 +1574,8 @@ int drm_atomic_helper_wait_for_fences(struct drm_device *dev,
 	struct drm_plane_state *new_plane_state;
 	int i, ret;
 
+	set_fence_deadline(dev, state);
+
 	for_each_new_plane_in_state(state, plane, new_plane_state, i) {
 		if (!new_plane_state->fence)
 			continue;
-- 
2.39.1
Re: [PATCH v9 11/15] drm/atomic-helper: Set fence deadline for vblank
Posted by Ville Syrjälä 3 years, 1 month ago 
On Thu, Mar 02, 2023 at 03:53:33PM -0800, Rob Clark wrote:
> From: Rob Clark <robdclark@chromium.org>
> 
> For an atomic commit updating a single CRTC (ie. a pageflip) calculate
> the next vblank time, and inform the fence(s) of that deadline.
> 
> v2: Comment typo fix (danvet)
> 
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
>  drivers/gpu/drm/drm_atomic_helper.c | 36 +++++++++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index d579fd8f7cb8..d8ee98ce2fc5 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -1511,6 +1511,40 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
>  }
>  EXPORT_SYMBOL(drm_atomic_helper_commit_modeset_enables);
>  
> +/*
> + * For atomic updates which touch just a single CRTC, calculate the time of the
> + * next vblank, and inform all the fences of the deadline.
> + */
> +static void set_fence_deadline(struct drm_device *dev,
> +			       struct drm_atomic_state *state)
> +{
> +	struct drm_crtc *crtc, *wait_crtc = NULL;
> +	struct drm_crtc_state *new_crtc_state;
> +	struct drm_plane *plane;
> +	struct drm_plane_state *new_plane_state;
> +	ktime_t vbltime;
> +	int i;
> +
> +	for_each_new_crtc_in_state (state, crtc, new_crtc_state, i) {
> +		if (wait_crtc)
> +			return;
> +		wait_crtc = crtc;
> +	}
> +
> +	/* If no CRTCs updated, then nothing to do: */
> +	if (!wait_crtc)
> +		return;

Is there an actual point in limiting this to single crtc updates?
That immediately excludes tiled displays/etc.

Handling an arbitrary number of crtcs shouldn't really be a lot
more complicated should it?

> +
> +	if (drm_crtc_next_vblank_start(wait_crtc, &vbltime))
> +		return;
> +
> +	for_each_new_plane_in_state (state, plane, new_plane_state, i) {
> +		if (!new_plane_state->fence)
> +			continue;
> +		dma_fence_set_deadline(new_plane_state->fence, vbltime);
> +	}
> +}
> +
>  /**
>   * drm_atomic_helper_wait_for_fences - wait for fences stashed in plane state
>   * @dev: DRM device
> @@ -1540,6 +1574,8 @@ int drm_atomic_helper_wait_for_fences(struct drm_device *dev,
>  	struct drm_plane_state *new_plane_state;
>  	int i, ret;
>  
> +	set_fence_deadline(dev, state);
> +
>  	for_each_new_plane_in_state(state, plane, new_plane_state, i) {
>  		if (!new_plane_state->fence)
>  			continue;
> -- 
> 2.39.1

-- 
Ville Syrjälä
Intel
Re: [PATCH v9 11/15] drm/atomic-helper: Set fence deadline for vblank
Posted by Rob Clark 3 years, 1 month ago 
On Fri, Mar 3, 2023 at 7:12 AM Ville Syrjälä
<ville.syrjala@linux.intel.com> wrote:
>
> On Thu, Mar 02, 2023 at 03:53:33PM -0800, Rob Clark wrote:
> > From: Rob Clark <robdclark@chromium.org>
> >
> > For an atomic commit updating a single CRTC (ie. a pageflip) calculate
> > the next vblank time, and inform the fence(s) of that deadline.
> >
> > v2: Comment typo fix (danvet)
> >
> > Signed-off-by: Rob Clark <robdclark@chromium.org>
> > Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Signed-off-by: Rob Clark <robdclark@chromium.org>
> > ---
> >  drivers/gpu/drm/drm_atomic_helper.c | 36 +++++++++++++++++++++++++++++
> >  1 file changed, 36 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> > index d579fd8f7cb8..d8ee98ce2fc5 100644
> > --- a/drivers/gpu/drm/drm_atomic_helper.c
> > +++ b/drivers/gpu/drm/drm_atomic_helper.c
> > @@ -1511,6 +1511,40 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
> >  }
> >  EXPORT_SYMBOL(drm_atomic_helper_commit_modeset_enables);
> >
> > +/*
> > + * For atomic updates which touch just a single CRTC, calculate the time of the
> > + * next vblank, and inform all the fences of the deadline.
> > + */
> > +static void set_fence_deadline(struct drm_device *dev,
> > +                            struct drm_atomic_state *state)
> > +{
> > +     struct drm_crtc *crtc, *wait_crtc = NULL;
> > +     struct drm_crtc_state *new_crtc_state;
> > +     struct drm_plane *plane;
> > +     struct drm_plane_state *new_plane_state;
> > +     ktime_t vbltime;
> > +     int i;
> > +
> > +     for_each_new_crtc_in_state (state, crtc, new_crtc_state, i) {
> > +             if (wait_crtc)
> > +                     return;
> > +             wait_crtc = crtc;
> > +     }
> > +
> > +     /* If no CRTCs updated, then nothing to do: */
> > +     if (!wait_crtc)
> > +             return;
>
> Is there an actual point in limiting this to single crtc updates?
> That immediately excludes tiled displays/etc.
>
> Handling an arbitrary number of crtcs shouldn't really be a lot
> more complicated should it?

I guess I could find the soonest upcoming vblank of all the CRTCs and
use that as the deadline?

BR,
-R

> > +
> > +     if (drm_crtc_next_vblank_start(wait_crtc, &vbltime))
> > +             return;
> > +
> > +     for_each_new_plane_in_state (state, plane, new_plane_state, i) {
> > +             if (!new_plane_state->fence)
> > +                     continue;
> > +             dma_fence_set_deadline(new_plane_state->fence, vbltime);
> > +     }
> > +}
> > +
> >  /**
> >   * drm_atomic_helper_wait_for_fences - wait for fences stashed in plane state
> >   * @dev: DRM device
> > @@ -1540,6 +1574,8 @@ int drm_atomic_helper_wait_for_fences(struct drm_device *dev,
> >       struct drm_plane_state *new_plane_state;
> >       int i, ret;
> >
> > +     set_fence_deadline(dev, state);
> > +
> >       for_each_new_plane_in_state(state, plane, new_plane_state, i) {
> >               if (!new_plane_state->fence)
> >                       continue;
> > --
> > 2.39.1
>
> --
> Ville Syrjälä
> Intel
Re: [PATCH v9 11/15] drm/atomic-helper: Set fence deadline for vblank
Posted by Ville Syrjälä 3 years, 1 month ago 
On Fri, Mar 03, 2023 at 07:45:05AM -0800, Rob Clark wrote:
> On Fri, Mar 3, 2023 at 7:12 AM Ville Syrjälä
> <ville.syrjala@linux.intel.com> wrote:
> >
> > On Thu, Mar 02, 2023 at 03:53:33PM -0800, Rob Clark wrote:
> > > From: Rob Clark <robdclark@chromium.org>
> > >
> > > For an atomic commit updating a single CRTC (ie. a pageflip) calculate
> > > the next vblank time, and inform the fence(s) of that deadline.
> > >
> > > v2: Comment typo fix (danvet)
> > >
> > > Signed-off-by: Rob Clark <robdclark@chromium.org>
> > > Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > > Signed-off-by: Rob Clark <robdclark@chromium.org>
> > > ---
> > >  drivers/gpu/drm/drm_atomic_helper.c | 36 +++++++++++++++++++++++++++++
> > >  1 file changed, 36 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> > > index d579fd8f7cb8..d8ee98ce2fc5 100644
> > > --- a/drivers/gpu/drm/drm_atomic_helper.c
> > > +++ b/drivers/gpu/drm/drm_atomic_helper.c
> > > @@ -1511,6 +1511,40 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
> > >  }
> > >  EXPORT_SYMBOL(drm_atomic_helper_commit_modeset_enables);
> > >
> > > +/*
> > > + * For atomic updates which touch just a single CRTC, calculate the time of the
> > > + * next vblank, and inform all the fences of the deadline.
> > > + */
> > > +static void set_fence_deadline(struct drm_device *dev,
> > > +                            struct drm_atomic_state *state)
> > > +{
> > > +     struct drm_crtc *crtc, *wait_crtc = NULL;
> > > +     struct drm_crtc_state *new_crtc_state;
> > > +     struct drm_plane *plane;
> > > +     struct drm_plane_state *new_plane_state;
> > > +     ktime_t vbltime;
> > > +     int i;
> > > +
> > > +     for_each_new_crtc_in_state (state, crtc, new_crtc_state, i) {
> > > +             if (wait_crtc)
> > > +                     return;
> > > +             wait_crtc = crtc;
> > > +     }
> > > +
> > > +     /* If no CRTCs updated, then nothing to do: */
> > > +     if (!wait_crtc)
> > > +             return;
> >
> > Is there an actual point in limiting this to single crtc updates?
> > That immediately excludes tiled displays/etc.
> >
> > Handling an arbitrary number of crtcs shouldn't really be a lot
> > more complicated should it?
> 
> I guess I could find the soonest upcoming vblank of all the CRTCs and
> use that as the deadline?

Yeah, that seems reasonable. The flips are supposed to happen
atomically (if possible) anyway so collapsing the thing to
a single deadline for all makes sense to me.

-- 
Ville Syrjälä
Intel

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