[Intel-gfx] [PATCH 05/12] drm/i915: Kill off intel_crtc->atomic.wait_vblank, v2.

[Imre Deak]

On ke, 2015-11-25 at 14:21 +0200, Ander Conselvan De Oliveira wrote:
> On Thu, 2015-11-19 at 16:07 +0100, Maarten Lankhorst wrote:
> > Currently we perform our own wait in post_plane_update,
> > but the atomic core performs another one in wait_for_vblanks.
> > This means that 2 vblanks are done when a fb is changed,
> > which is a bit overkill.
> > 
> > Merge them by creating a helper function that takes a crtc mask
> > for the planes to wait on.
> > 
> > The broadwell vblank workaround may look gone entirely but this is
> > not the case. pipe_config->wm_changed is set to true
> > when any plane is turned on, which forces a vblank wait.
> > 
> > Changes since v1:
> > - Removing the double vblank wait on broadwell moved to its own commit.
> > 
> > Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_atomic.c  |  1 +
> >  drivers/gpu/drm/i915/intel_display.c | 88 ++++++++++++++++++++++++++---------
> > -
> >  drivers/gpu/drm/i915/intel_drv.h     |  2 +-
> >  3 files changed, 65 insertions(+), 26 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_atomic.c
> > b/drivers/gpu/drm/i915/intel_atomic.c
> > index 4625f8a9ba12..8e579a8505ac 100644
> > --- a/drivers/gpu/drm/i915/intel_atomic.c
> > +++ b/drivers/gpu/drm/i915/intel_atomic.c
> > @@ -97,6 +97,7 @@ intel_crtc_duplicate_state(struct drm_crtc *crtc)
> >  	crtc_state->disable_lp_wm = false;
> >  	crtc_state->disable_cxsr = false;
> >  	crtc_state->wm_changed = false;
> > +	crtc_state->fb_changed = false;
> >  
> >  	return &crtc_state->base;
> >  }
> > diff --git a/drivers/gpu/drm/i915/intel_display.c
> > b/drivers/gpu/drm/i915/intel_display.c
> > index 60f17bc5f0ce..299edbf6f99e 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -4738,9 +4738,6 @@ static void intel_post_plane_update(struct intel_crtc
> > *crtc)
> >  	struct drm_device *dev = crtc->base.dev;
> >  	struct drm_i915_private *dev_priv = dev->dev_private;
> >  
> > -	if (atomic->wait_vblank)
> > -		intel_wait_for_vblank(dev, crtc->pipe);
> > -
> >  	intel_frontbuffer_flip(dev, atomic->fb_bits);
> >  
> >  	crtc->wm.cxsr_allowed = true;
> > @@ -4754,6 +4751,9 @@ static void intel_post_plane_update(struct intel_crtc
> > *crtc)
> >  	if (atomic->post_enable_primary)
> >  		intel_post_enable_primary(&crtc->base);
> >  
> > +	if (needs_modeset(&pipe_config->base))
> > +		intel_display_power_put(dev_priv, POWER_DOMAIN_MODESET);
> > +
> >  	memset(atomic, 0, sizeof(*atomic));
> >  }
> >  
> > @@ -11693,6 +11693,9 @@ int intel_plane_atomic_calc_changes(struct
> > drm_crtc_state *crtc_state,
> >  	if (!was_visible && !visible)
> >  		return 0;
> >  
> > +	if (fb != old_plane_state->base.fb)
> > +		pipe_config->fb_changed = true;
> > +
> >  	turn_off = was_visible && (!visible || mode_changed);
> >  	turn_on = visible && (!was_visible || mode_changed);
> >  
> > @@ -11708,8 +11711,6 @@ int intel_plane_atomic_calc_changes(struct
> > drm_crtc_state *crtc_state,
> >  
> >  		/* must disable cxsr around plane enable/disable */
> >  		if (plane->type != DRM_PLANE_TYPE_CURSOR) {
> > -			if (is_crtc_enabled)
> > -				intel_crtc->atomic.wait_vblank = true;
> >  			pipe_config->disable_cxsr = true;
> >  		}
> >  	} else if ((was_visible || visible) &&
> > @@ -11757,14 +11758,6 @@ int intel_plane_atomic_calc_changes(struct
> > drm_crtc_state *crtc_state,
> >  		    plane_state->rotation != BIT(DRM_ROTATE_0))
> >  			intel_crtc->atomic.disable_fbc = true;
> >  
> > -		/*
> > -		 * BDW signals flip done immediately if the plane
> > -		 * is disabled, even if the plane enable is already
> > -		 * armed to occur at the next vblank :(
> > -		 */
> > -		if (turn_on && IS_BROADWELL(dev))
> > -			intel_crtc->atomic.wait_vblank = true;
> > -
> >  		intel_crtc->atomic.update_fbc |= visible || mode_changed;
> >  		break;
> >  	case DRM_PLANE_TYPE_CURSOR:
> > @@ -11779,12 +11772,10 @@ int intel_plane_atomic_calc_changes(struct
> > drm_crtc_state *crtc_state,
> >  		if (IS_IVYBRIDGE(dev) &&
> >  		    needs_scaling(to_intel_plane_state(plane_state)) &&
> >  		    !needs_scaling(old_plane_state)) {
> > -			to_intel_crtc_state(crtc_state)->disable_lp_wm =
> > true;
> > -		} else if (turn_off && !mode_changed) {
> > -			intel_crtc->atomic.wait_vblank = true;
> > +			pipe_config->disable_lp_wm = true;
> > +		} else if (turn_off && !mode_changed)
> >  			intel_crtc->atomic.update_sprite_watermarks |=
> >  				1 << i;
> > -		}
> >  
> >  		break;
> >  	}
> > @@ -13299,6 +13290,48 @@ static int intel_atomic_prepare_commit(struct
> > drm_device *dev,
> >  	return ret;
> >  }
> >  
> > +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 drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
> > +
> > +		if (!((1 << pipe) & crtc_mask))
> > +			continue;
> > +
> > +		ret = drm_crtc_vblank_get(crtc);
> > +		if (ret != 0) {
> > +			crtc_mask &= ~(1 << pipe);
> > +			continue;
> > +		}
> > +
> > +		last_vblank_count[pipe] = drm_crtc_vblank_count(crtc);
> > +	}
> > +
> > +	for_each_pipe(dev_priv, pipe) {
> > +		struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
> > +
> > +		if (!((1 << pipe) & crtc_mask))
> > +			continue;
> > +
> > +		wait_event_timeout(dev->vblank[pipe].queue,
> > +				last_vblank_count[pipe] !=
> > +					drm_crtc_vblank_count(crtc),
> > +				msecs_to_jiffies(50));
> > +
> > +		drm_crtc_vblank_put(crtc);
> > +	}
> > +}
> > +
> > +
> >  /**
> >   * intel_atomic_commit - commit validated state object
> >   * @dev: DRM device
> > @@ -13325,6 +13358,7 @@ static int intel_atomic_commit(struct drm_device *dev,
> >  	struct drm_crtc *crtc;
> >  	int ret = 0, i;
> >  	bool hw_check = intel_state->modeset;
> > +	unsigned crtc_vblank_mask = 0;
> >  
> >  	ret = intel_atomic_prepare_commit(dev, state, async);
> >  	if (ret) {
> > @@ -13375,8 +13409,9 @@ static int intel_atomic_commit(struct drm_device *dev,
> >  	for_each_crtc_in_state(state, crtc, crtc_state, i) {
> >  		struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> >  		bool modeset = needs_modeset(crtc->state);
> > -		bool update_pipe = !modeset &&
> > -			to_intel_crtc_state(crtc->state)->update_pipe;
> > +		struct intel_crtc_state *pipe_config =
> > +			to_intel_crtc_state(crtc->state);
> > +		bool update_pipe = !modeset && pipe_config->update_pipe;
> >  		unsigned long put_domains = 0;
> >  
> >  		if (modeset)
> > @@ -13401,18 +13436,21 @@ static int intel_atomic_commit(struct drm_device
> > *dev,
> >  		    (crtc->state->planes_changed || update_pipe))
> >  			drm_atomic_helper_commit_planes_on_crtc(crtc_state);
> >  
> > +		if (pipe_config->base.active &&
> > +		    (pipe_config->wm_changed || pipe_config->disable_cxsr ||
> > +		     pipe_config->fb_changed))
> > +			crtc_vblank_mask |= 1 << i;
> > +
> >  		if (put_domains)
> >  			modeset_put_power_domains(dev_priv, put_domains);
> > -
> > -		intel_post_plane_update(intel_crtc);
> > -
> > -		if (modeset)
> > -			intel_display_power_put(dev_priv, POWER_DOMAIN_MODESET);
> 
> Would it be too evil to move the power domain get/put out of the loop? If I
> understand correctly, intel_state->modeset already tells us if there is any crtc
> that needs a modeset, so we could just protect the calls with that. I'm not sure
> what is the impact, but at least we could avoid having the get in
> intel_atomic_commit() and the put in intel_post_plane_enable().

Yes, that's cleaner, and possibly avoids some unnecessary on/off toggling of
power wells. We could've done this already earlier using the existing any_ms flag..

Btw, not the problem in this patch, but I just noticed we should take the modeset
power domain already earlier. We are disabling at least CRTCs/PLLs already earlier
which is in the set of operations we need to protect with this power domain. That
could be fixed as a follow-up.

--Imre

> 
> Ander
> 
> >  	}
> >  
> >  	/* FIXME: add subpixel order */
> >  
> > -	drm_atomic_helper_wait_for_vblanks(dev, state);
> > +	intel_atomic_wait_for_vblanks(dev, dev_priv, crtc_vblank_mask);
> > +
> > +	for_each_crtc_in_state(state, crtc, crtc_state, i)
> > +		intel_post_plane_update(to_intel_crtc(crtc));
> >  
> >  	mutex_lock(&dev->struct_mutex);
> >  	drm_atomic_helper_cleanup_planes(dev, state);
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h
> > b/drivers/gpu/drm/i915/intel_drv.h
> > index db61c37dbf09..66f66740ccaa 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -373,6 +373,7 @@ struct intel_crtc_state {
> >  	bool update_pipe; /* can a fast modeset be performed? */
> >  	bool disable_cxsr;
> >  	bool wm_changed; /* watermarks are updated */
> > +	bool fb_changed; /* fb on any of the planes is changed */
> >  
> >  	/* Pipe source size (ie. panel fitter input size)
> >  	 * All planes will be positioned inside this space,
> > @@ -539,7 +540,6 @@ struct intel_crtc_atomic_commit {
> >  
> >  	/* Sleepable operations to perform after commit */
> >  	unsigned fb_bits;
> > -	bool wait_vblank;
> >  	bool update_fbc;
> >  	bool post_enable_primary;
> >  	unsigned update_sprite_watermarks;