[Intel-gfx] [PATCH] drm/i915: force full modeset if the connector is in DPMS OFF mode

[Imre Deak]

Currently the driver's assumed behavior for a modeset with an attached
FB is that the corresponding connector will be switched to DPMS ON mode
if it happened to be in DPMS OFF (or another power save mode). This
wasn't enforced though if only the FB changed, everything else (format,
connector etc.) remaining the same. In this case we only set the new FB
base and left the connector in the old power save mode.

Fix this by forcing a full modeset whenever there is an attached FB and
any affected connector is in a power save mode.

Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 drivers/gpu/drm/i915/intel_display.c |   21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 2939524..0aee2ba 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8380,6 +8380,21 @@ static void intel_set_config_restore_state(struct drm_device *dev,
 	}
 }
 
+static bool
+crtc_connector_off(struct drm_crtc *crtc, struct drm_connector *connectors,
+		   int num_connectors)
+{
+	int i;
+
+	for (i = 0; i < num_connectors; i++)
+		if (connectors[i].encoder &&
+		    connectors[i].encoder->crtc == crtc &&
+		    connectors[i].dpms != DRM_MODE_DPMS_ON)
+			return true;
+
+	return false;
+}
+
 static void
 intel_set_config_compute_mode_changes(struct drm_mode_set *set,
 				      struct intel_set_config *config)
@@ -8397,8 +8412,12 @@ intel_set_config_compute_mode_changes(struct drm_mode_set *set,
 		} else if (set->fb->pixel_format !=
 			   set->crtc->fb->pixel_format) {
 			config->mode_changed = true;
-		} else
+		} else if (crtc_connector_off(set->crtc, *set->connectors,
+					      set->num_connectors)) {
+			config->mode_changed = true;
+		} else {
 			config->fb_changed = true;
+		}
 	}
 
 	if (set->fb && (set->x != set->crtc->x || set->y != set->crtc->y))
-- 
1.7.10.4