[Intel-gfx] [PATCH 2/2] drm/i915: calculate pfit changes in set_config v3

[Jesse Barnes]

This should allow us to avoid mode sets for some panel fitter config
changes.

v2:
  - fixup pfit comment (Ander)
v3:
  - fixup pfit disable shortcut, only apply to gen4 for now (Jesse)

Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
---
 drivers/gpu/drm/i915/intel_display.c | 73 ++++++++++++++++++++++++++++++------
 1 file changed, 62 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 58ed4ef..e7175b1 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2861,17 +2861,8 @@ static void intel_update_pipe_size(struct intel_crtc *crtc)
 		return;
 
 	/*
-	 * Update pipe size and adjust fitter if needed: the reason for this is
-	 * that in compute_mode_changes we check the native mode (not the pfit
-	 * mode) to see if we can flip rather than do a full mode set. In the
-	 * fastboot case, we'll flip, but if we don't update the pipesrc and
-	 * pfit state, we'll end up with a big fb scanned out into the wrong
-	 * sized surface.
-	 *
-	 * To fix this properly, we need to hoist the checks up into
-	 * compute_mode_changes (or above), check the actual pfit state and
-	 * whether the platform allows pfit disable with pipe active, and only
-	 * then update the pipesrc and pfit state, even on the flip path.
+	 * See intel_pfit_changed for info on when we're allowed to
+	 * do this w/o a pipe shutdown.
 	 */
 
 	adjusted_mode = &crtc->config.adjusted_mode;
@@ -11266,6 +11257,62 @@ static void disable_crtc_nofb(struct intel_crtc *crtc)
 	crtc->new_config = NULL;
 }
 
+/* Do we need a mode set due to pfit changes? */
+static bool intel_pfit_changed(struct drm_device *dev,
+			       struct intel_crtc_config *new_config,
+			       struct intel_crtc_config *cur_config)
+{
+	bool ret = false;
+
+	if (HAS_DDI(dev) || HAS_PCH_SPLIT(dev)) {
+		/*
+		 * On PCH platforms we can disable pfit w/o a pipe shutdown,
+		 * otherwise we'll need a mode set.
+		 */
+		if (new_config->pch_pfit.enabled &&
+		    cur_config->pch_pfit.enabled)
+			ret = false;
+		else if (new_config->pch_pfit.enabled &&
+			 !cur_config->pch_pfit.enabled)
+			ret = true;
+		else if (!new_config->pch_pfit.enabled &&
+			 cur_config->pch_pfit.enabled)
+			ret = false;
+		else if (!new_config->pch_pfit.enabled &&
+			 !cur_config->pch_pfit.enabled)
+			ret = false;
+	} else if (IS_GEN4(dev)) {
+		/*
+		 * We may be able to get away with this on more chips, but
+		 * we need more testing here.
+		 */
+		bool new_enabled, old_enabled;
+
+		new_enabled = !!(new_config->gmch_pfit.control & PFIT_ENABLE);
+		old_enabled = !!(cur_config->gmch_pfit.control & PFIT_ENABLE);
+
+		/* 9xx only needs a shutdown to disable pfit */
+		if (new_enabled && old_enabled)
+			ret = false;
+		else if (new_enabled && !old_enabled)
+			ret = false;
+		else if (!new_enabled && old_enabled)
+			ret = true;
+		else if (!new_enabled && !old_enabled)
+			ret = false;
+	} else {
+		bool new_enabled, old_enabled;
+
+		new_enabled = !!(new_config->gmch_pfit.control & PFIT_ENABLE);
+		old_enabled = !!(cur_config->gmch_pfit.control & PFIT_ENABLE);
+
+		if (new_enabled != old_enabled)
+			ret = true;
+	}
+
+	return ret;
+}
+
 static int intel_crtc_set_config(struct drm_mode_set *set)
 {
 	struct drm_device *dev;
@@ -11334,6 +11381,10 @@ static int intel_crtc_set_config(struct drm_mode_set *set)
 		if (to_intel_crtc(set->crtc)->new_config->has_infoframe ||
 		    to_intel_crtc(set->crtc)->config.has_infoframe)
 			config->mode_changed = true;
+
+		if (intel_pfit_changed(dev, to_intel_crtc(set->crtc)->new_config,
+				       &to_intel_crtc(set->crtc)->config))
+			config->mode_changed = true;
 	}
 
 	/* set_mode will free it in the mode_changed case */
-- 
1.9.1