| Message ID | 20210726233854.2453899-4-robdclark@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | dma-fence: Deadline awareness | expand |
On 2021-07-27 1:38 a.m., 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. > > 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 bc3487964fb5..f81b20775b15 100644 > --- a/drivers/gpu/drm/drm_atomic_helper.c > +++ b/drivers/gpu/drm/drm_atomic_helper.c > @@ -1406,6 +1406,40 @@ 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 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; Either this return or the next one below would always be taken, I doubt this was intended. > + wait_crtc = crtc; > + } > + > + /* If no CRTCs updated, then nothing to do: */ > + if (!wait_crtc) > + return; > + > + if (drm_crtc_next_vblank_time(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); > + } vblank timestamps correspond to the end of vertical blank, the deadline should be the start of vertical blank though.
On Tue, Jul 27, 2021 at 3:44 AM Michel Dänzer <michel@daenzer.net> wrote: > > On 2021-07-27 1:38 a.m., 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. > > > > 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 bc3487964fb5..f81b20775b15 100644 > > --- a/drivers/gpu/drm/drm_atomic_helper.c > > +++ b/drivers/gpu/drm/drm_atomic_helper.c > > @@ -1406,6 +1406,40 @@ 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 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; > > Either this return or the next one below would always be taken, I doubt this was intended. oops, the condition here is mistakenly inverted, it was meant to bail if there is more than a single CRTC > > > + wait_crtc = crtc; > > + } > > + > > + /* If no CRTCs updated, then nothing to do: */ > > + if (!wait_crtc) > > + return; > > + > > + if (drm_crtc_next_vblank_time(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); > > + } > > vblank timestamps correspond to the end of vertical blank, the deadline should be the start of vertical blank though. > hmm, I suppose this depends on whether the hw actually has separate irq's for frame-done and vblank (and whether the driver differentiates).. and if the display controller is doing some buffering, the point at which it wants to flip could be a bit earlier still. Maybe we just want a kms driver provided offset for how early it wants the deadline relative to vblank? BR, -R > > -- > Earthling Michel Dänzer | https://redhat.com > Libre software enthusiast | Mesa and X developer
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index bc3487964fb5..f81b20775b15 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -1406,6 +1406,40 @@ 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 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_time(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 @@ -1435,6 +1469,8 @@ 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;