[PATCH 5/6] drm/i915/display: Check if pipe fastset is allowed by external dependencies

[José Roberto de Souza]

Check if fastset is allowed by external dependencies like other pipes
and transcoders.

Right now this patch only forces a fullmodeset in MST slaves of MST
masters that needs a fullmodeset but it will be needed for port sync
as well.

v3:
- moved handling to intel_atomic_check() this way is guarantee that
all pipes will have its state computed

v4:
- added a function to return if MST master neeeds modeset to simply
code in intel_atomic_check()

v5:
- fixed and moved code to check if MST master needs a modeset

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Lucas De Marchi <lucas.demarchi at intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Manasi Navare <manasi.d.navare at intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 69 ++++++++++++++++----
 1 file changed, 56 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index a4f252d05b37..d9e8fb2db7c6 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -13903,19 +13903,6 @@ static void intel_crtc_check_fastset(const struct intel_crtc_state *old_crtc_sta
 
 	new_crtc_state->uapi.mode_changed = false;
 	new_crtc_state->update_pipe = true;
-
-	/*
-	 * If we're not doing the full modeset we want to
-	 * keep the current M/N values as they may be
-	 * sufficiently different to the computed values
-	 * to cause problems.
-	 *
-	 * FIXME: should really copy more fuzzy state here
-	 */
-	new_crtc_state->fdi_m_n = old_crtc_state->fdi_m_n;
-	new_crtc_state->dp_m_n = old_crtc_state->dp_m_n;
-	new_crtc_state->dp_m2_n2 = old_crtc_state->dp_m2_n2;
-	new_crtc_state->has_drrs = old_crtc_state->has_drrs;
 }
 
 static int intel_crtc_add_planes_to_state(struct intel_atomic_state *state,
@@ -14026,6 +14013,20 @@ static int intel_atomic_check_crtcs(struct intel_atomic_state *state)
 	return 0;
 }
 
+static bool intel_cpu_transcoder_needs_modeset(struct intel_atomic_state *state,
+					       enum transcoder transcoder)
+{
+	struct intel_crtc_state *new_crtc_state;
+	struct intel_crtc *crtc;
+	int i;
+
+	for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i)
+		if (new_crtc_state->cpu_transcoder == transcoder)
+			return needs_modeset(new_crtc_state);
+
+	return false;
+}
+
 /**
  * intel_atomic_check - validate state object
  * @dev: drm device
@@ -14083,6 +14084,48 @@ static int intel_atomic_check(struct drm_device *dev,
 			any_ms = true;
 	}
 
+	/**
+	 * Check if fastset is allowed by external dependencies like other
+	 * pipes and transcoders.
+	 *
+	 * Right now it only forces a fullmodeset when the MST master
+	 * transcoder did not changed but the pipe of the master transcoder
+	 * needs a fullmodeset so all slaves also needs to do a fullmodeset.
+	 */
+	for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i) {
+		enum transcoder master = new_crtc_state->mst_master_transcoder;
+
+		if (!intel_dp_mst_is_slave_trans(new_crtc_state) ||
+		    needs_modeset(new_crtc_state))
+			continue;
+
+		if (intel_cpu_transcoder_needs_modeset(state, master)) {
+			new_crtc_state->uapi.mode_changed = true;
+			new_crtc_state->update_pipe = false;
+		}
+	}
+
+	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,
+					    new_crtc_state, i) {
+		if (needs_modeset(new_crtc_state)) {
+			WARN_ON(!new_crtc_state->update_pipe);
+			continue;
+		}
+
+		/*
+		 * If we're not doing the full modeset we want to
+		 * keep the current M/N values as they may be
+		 * sufficiently different to the computed values
+		 * to cause problems.
+		 *
+		 * FIXME: should really copy more fuzzy state here
+		 */
+		new_crtc_state->fdi_m_n = old_crtc_state->fdi_m_n;
+		new_crtc_state->dp_m_n = old_crtc_state->dp_m_n;
+		new_crtc_state->dp_m2_n2 = old_crtc_state->dp_m2_n2;
+		new_crtc_state->has_drrs = old_crtc_state->has_drrs;
+	}
+
 	if (any_ms && !check_digital_port_conflicts(state)) {
 		DRM_DEBUG_KMS("rejecting conflicting digital port configuration\n");
 		ret = EINVAL;
-- 
2.24.1