[Intel-gfx] [PATCH v2 18/40] drm/i915: Disable pipes in reverse order

[Lucas De Marchi]

From: José Roberto de Souza <jose.souza at intel.com>

Disable CRTC/pipes in reverse order because some features (MST in
TGL+) requires master and slave relationship between pipes, so it
should always pick the lowest pipe as master as it will be enabled
first and disable in the reverse order so the master will be the last
one to be disabled.

Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index b51d1ceb8739..ddb8436e2208 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -13908,7 +13908,15 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state)
 	if (state->modeset)
 		wakeref = intel_display_power_get(dev_priv, POWER_DOMAIN_MODESET);
 
-	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
+	/*
+	 * Disable CRTC/pipes in reverse order because some features(MST in
+	 * TGL+) requires master and slave relationship between pipes, so it
+	 * should always pick the lowest pipe as master as it will be enabled
+	 * first and disable in the reverse order so the master will be the
+	 * last one to be disabled.
+	 */
+	for_each_oldnew_intel_crtc_in_state_reverse(state, crtc, old_crtc_state,
+						    new_crtc_state, i) {
 		if (needs_modeset(new_crtc_state) ||
 		    new_crtc_state->update_pipe) {
 
-- 
2.21.0