Re: [RFC PATCH 1/5] drm/i915: Always wait for flip_done

Daniel Vetter
2017-08-30T13:40:31Z

On Wed, Aug 30, 2017 at 02:54:28PM +0200, Maarten Lankhorst wrote:
> Op 30-08-17 om 14:43 schreef Daniel Vetter:
> > On Wed, Aug 30, 2017 at 02:17:48PM +0200, Maarten Lankhorst wrote:
> >> The next commit removes the wait for flip_done in in
> >> drm_atomic_helper_commit_cleanup_done, but we need it for the tests
> >> to pass. Instead of using complicated vblank tracking which ends
> >> up being ignored anyway, call the correct atomic helper. :)
> >>
> >> RFC because I'm not completely sure what we want to do with the vblank waiting,
> >> I think for now this patch is the right way to go until we decide because it
> >> preserves the status quo when drm_crtc_commit was introduced.
> >>
> >> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> >> ---
> >> drivers/gpu/drm/i915/i915_drv.h | 3 +-
> >> drivers/gpu/drm/i915/intel_display.c | 83 +++---------------------------------
> >> 2 files changed, 8 insertions(+), 78 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> >> index cbbafbfb0a55..de19621864a9 100644
> >> --- a/drivers/gpu/drm/i915/i915_drv.h
> >> +++ b/drivers/gpu/drm/i915/i915_drv.h
> >> @@ -707,8 +707,7 @@ struct drm_i915_display_funcs {
> >> struct drm_atomic_state *old_state);
> >> void (*crtc_disable)(struct intel_crtc_state *old_crtc_state,
> >> struct drm_atomic_state *old_state);
> >> - void (*update_crtcs)(struct drm_atomic_state *state,
> >> - unsigned int *crtc_vblank_mask);
> >> + void (*update_crtcs)(struct drm_atomic_state *state);
> >> void (*audio_codec_enable)(struct drm_connector *connector,
> >> struct intel_encoder *encoder,
> >> const struct drm_display_mode *adjusted_mode);
> >> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> >> index 52c73b4dabaa..3f3cb96aa11e 100644
> >> --- a/drivers/gpu/drm/i915/intel_display.c
> >> +++ b/drivers/gpu/drm/i915/intel_display.c
> >> @@ -12114,73 +12114,10 @@ u32 intel_crtc_get_vblank_counter(struct intel_crtc *crtc)
> >> return dev->driver->get_vblank_counter(dev, crtc->pipe);
> >> }
> >>
> >> -static void intel_atomic_wait_for_vblanks(struct drm_device *dev,
> >> - struct drm_i915_private *dev_priv,
> >> - unsigned crtc_mask)
> >> -{
> >> - unsigned last_vblank_count[I915_MAX_PIPES];
> >> - enum pipe pipe;
> >> - int ret;
> >> -
> >> - if (!crtc_mask)
> >> - return;
> >> -
> >> - for_each_pipe(dev_priv, pipe) {
> >> - struct intel_crtc *crtc = intel_get_crtc_for_pipe(dev_priv,
> >> - pipe);
> >> -
> >> - if (!((1 << pipe) & crtc_mask))
> >> - continue;
> >> -
> >> - ret = drm_crtc_vblank_get(&crtc->base);
> >> - if (WARN_ON(ret != 0)) {
> >> - crtc_mask &= ~(1 << pipe);
> >> - continue;
> >> - }
> >> -
> >> - last_vblank_count[pipe] = drm_crtc_vblank_count(&crtc->base);
> >> - }
> >> -
> >> - for_each_pipe(dev_priv, pipe) {
> >> - struct intel_crtc *crtc = intel_get_crtc_for_pipe(dev_priv,
> >> - pipe);
> >> - long lret;
> >> -
> >> - if (!((1 << pipe) & crtc_mask))
> >> - continue;
> >> -
> >> - lret = wait_event_timeout(dev->vblank[pipe].queue,
> >> - last_vblank_count[pipe] !=
> >> - drm_crtc_vblank_count(&crtc->base),
> >> - msecs_to_jiffies(50));
> >> -
> >> - WARN(!lret, "pipe %c vblank wait timed out\n", pipe_name(pipe));
> >> -
> >> - drm_crtc_vblank_put(&crtc->base);
> >> - }
> >> -}
> >> -
> >> -static bool needs_vblank_wait(struct intel_crtc_state *crtc_state)
> >> -{
> >> - /* fb updated, need to unpin old fb */
> >> - if (crtc_state->fb_changed)
> >> - return true;
> >> -
> >> - /* wm changes, need vblank before final wm's */
> >> - if (crtc_state->update_wm_post)
> >> - return true;
> >> -
> >> - if (crtc_state->wm.need_postvbl_update)
> >> - return true;
> >> -
> >> - return false;
> >> -}
> >> -
> >> static void intel_update_crtc(struct drm_crtc *crtc,
> >> struct drm_atomic_state *state,
> >> struct drm_crtc_state *old_crtc_state,
> >> - struct drm_crtc_state *new_crtc_state,
> >> - unsigned int *crtc_vblank_mask)
> >> + struct drm_crtc_state *new_crtc_state)
> >> {
> >> struct drm_device *dev = crtc->dev;
> >> struct drm_i915_private *dev_priv = to_i915(dev);
> >> @@ -12203,13 +12140,9 @@ static void intel_update_crtc(struct drm_crtc *crtc,
> >> }
> >>
> >> drm_atomic_helper_commit_planes_on_crtc(old_crtc_state);
> >> -
> >> - if (needs_vblank_wait(pipe_config))
> >> - *crtc_vblank_mask |= drm_crtc_mask(crtc);
> >> }
> >>
> >> -static void intel_update_crtcs(struct drm_atomic_state *state,
> >> - unsigned int *crtc_vblank_mask)
> >> +static void intel_update_crtcs(struct drm_atomic_state *state)
> >> {
> >> struct drm_crtc *crtc;
> >> struct drm_crtc_state *old_crtc_state, *new_crtc_state;
> >> @@ -12220,12 +12153,11 @@ static void intel_update_crtcs(struct drm_atomic_state *state,
> >> continue;
> >>
> >> intel_update_crtc(crtc, state, old_crtc_state,
> >> - new_crtc_state, crtc_vblank_mask);
> >> + new_crtc_state);
> >> }
> >> }
> >>
> >> -static void skl_update_crtcs(struct drm_atomic_state *state,
> >> - unsigned int *crtc_vblank_mask)
> >> +static void skl_update_crtcs(struct drm_atomic_state *state)
> >> {
> >> struct drm_i915_private *dev_priv = to_i915(state->dev);
> >> struct intel_atomic_state *intel_state = to_intel_atomic_state(state);
> >> @@ -12284,7 +12216,7 @@ static void skl_update_crtcs(struct drm_atomic_state *state,
> >> vbl_wait = true;
> >>
> >> intel_update_crtc(crtc, state, old_crtc_state,
> >> - new_crtc_state, crtc_vblank_mask);
> >> + new_crtc_state);
> >>
> >> if (vbl_wait)
> >> intel_wait_for_vblank(dev_priv, pipe);
> >> @@ -12346,7 +12278,6 @@ static void intel_atomic_commit_tail(struct drm_atomic_state *state)
> >> struct intel_crtc_state *intel_cstate;
> >> bool hw_check = intel_state->modeset;
> >> u64 put_domains[I915_MAX_PIPES] = {};
> >> - unsigned crtc_vblank_mask = 0;
> >> int i;
> >>
> >> intel_atomic_commit_fence_wait(intel_state);
> >> @@ -12438,7 +12369,7 @@ static void intel_atomic_commit_tail(struct drm_atomic_state *state)
> >> pm_qos_update_request(&dev_priv->pm_qos_atomic, 0);
> >>
> >> /* Now enable the clocks, plane, pipe, and connectors that we set up. */
> >> - dev_priv->display.update_crtcs(state, &crtc_vblank_mask);
> >> + dev_priv->display.update_crtcs(state);
> >>
> >> /* FIXME: We should call drm_atomic_helper_commit_hw_done() here
> >> * already, but still need the state for the delayed optimization. To
> >> @@ -12450,7 +12381,7 @@ static void intel_atomic_commit_tail(struct drm_atomic_state *state)
> >> * we don't need out special handling any more.
> >> */
> >> if (!state->legacy_cursor_update)
> > I think this if is dead code, since either we use the fastpath in
> > intel_legacy_cursor_update, which means no atomic commit. Or we don't, and
> > then we clear this hack (on most platforms at least) since it just wreaks
> > complete havoc.
> >
> > We should probably do this logic in the async helpers, i.e. if async
> > helpers reject a cursor update, clear state->legacy_cursor_update.
> >
> > Since I think we don't necessarily need this patch in this series, I think
> > it'd be better in a separate series to straighten out the async_update
> > story. Which would then include moving i915 over to the core support.
> Erm, not sure what you mean here, isn't state->legacy_cursor_update mostly false, which means in most cases we'll wait?

Yup. And the few cases where it's true should be handled by the
fastpath/async plane update logic. Would allow us to ditch a few
conditions all over the code.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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