Re: [PATCH v2 2/9] drm/i915: Kill off intel_crtc->atomic.wait_vblank, v3.

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Jan 11, 2016 at 01:27:42PM +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.

Still NAK, because you just removed the comment entirely.

> 
> Changes since v1:
> - Removing the double vblank wait on broadwell moved to its own commit.
> Changes since v2:
> - Move out POWER_DOMAIN_MODESET handling to its own commit.
> 
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_atomic.c  |  1 +
>  drivers/gpu/drm/i915/intel_display.c | 80 ++++++++++++++++++++++++++----------
>  drivers/gpu/drm/i915/intel_drv.h     |  2 +-
>  3 files changed, 61 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_atomic.c b/drivers/gpu/drm/i915/intel_atomic.c
> index 9682d94af710..ba9a57f33c43 100644
> --- a/drivers/gpu/drm/i915/intel_atomic.c
> +++ b/drivers/gpu/drm/i915/intel_atomic.c
> @@ -98,6 +98,7 @@ intel_crtc_duplicate_state(struct drm_crtc *crtc)
>  	crtc_state->disable_cxsr = false;
>  	crtc_state->wm_changed = false;
>  	crtc_state->wm.need_postvbl_update = 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 2aa1c5367625..eac73f005a70 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -4796,9 +4796,6 @@ static void intel_post_plane_update(struct intel_crtc *crtc)
>  		to_intel_crtc_state(crtc->base.state);
>  	struct drm_device *dev = crtc->base.dev;
>  
> -	if (atomic->wait_vblank)
> -		intel_wait_for_vblank(dev, crtc->pipe);
> -
>  	intel_frontbuffer_flip(dev, atomic->fb_bits);
>  
>  	crtc->wm.cxsr_allowed = true;
> @@ -11872,6 +11869,9 @@ 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;

Isn't that going to slow down cursor updates once again?

> +
>  	turn_off = was_visible && (!visible || mode_changed);
>  	turn_on = visible && (!was_visible || mode_changed);
>  
> @@ -11887,8 +11887,6 @@ 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 (intel_wm_need_update(plane, plane_state)) {
> @@ -11940,14 +11938,6 @@ 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:
> @@ -11962,12 +11952,10 @@ 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;
>  	}
> @@ -13509,6 +13497,48 @@ 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
> @@ -13537,6 +13567,7 @@ static int intel_atomic_commit(struct drm_device *dev,
>  	int ret = 0, i;
>  	bool hw_check = intel_state->modeset;
>  	unsigned long put_domains[I915_MAX_PIPES] = {};
> +	unsigned crtc_vblank_mask = 0;
>  
>  	ret = intel_atomic_prepare_commit(dev, state, async);
>  	if (ret) {
> @@ -13608,8 +13639,9 @@ 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;
>  
>  		if (modeset && crtc->state->active) {
>  			update_scanline_offset(to_intel_crtc(crtc));
> @@ -13623,12 +13655,18 @@ static int intel_atomic_commit(struct drm_device *dev,
>  		    (crtc->state->planes_changed || update_pipe))
>  			drm_atomic_helper_commit_planes_on_crtc(crtc_state);
>  
> -		intel_post_plane_update(intel_crtc);
> +		if (pipe_config->base.active &&
> +		    (pipe_config->wm_changed || pipe_config->disable_cxsr ||
> +		     pipe_config->fb_changed))
> +			crtc_vblank_mask |= 1 << i;
>  	}
>  
>  	/* 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));
>  
>  	/*
>  	 * Now that the vblank has passed, we can go ahead and program the
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index bdfe4035e074..8940aa4cf50c 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -385,6 +385,7 @@ 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,
> @@ -570,7 +571,6 @@ 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;
> -- 
> 2.1.0
> 
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-- 
Ville Syrjälä
Intel OTC
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