drm/i915: Update connector_mask during readout, v2.

BugLink: http://bugs.launchpad.net/bugs/1540390

drm/i915: Update connector_mask during readout, v2.

The connector_mask may be used any time during the non-atomic
.crtc_disable which is called before the full atomic state is
set up and needs to be accurate for that reason.

Changes since v1:
- Update connector_mask in readout_hw_state and add a comment.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/568D1C55.8010001@linux.intel.comSigned-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit 2aa974c9)
Signed-off-by: Timo Aaltonen <timo.aaltonen@canonical.com>
Signed-off-by: Andy Whitcroft <apw@canonical.com>

drivers/gpu/drm/i915/intel_display.c

@@ -15111,6 +15111,7 @@ static void intel_sanitize_crtc(struct intel_crtc *crtc)
 		WARN_ON(drm_atomic_set_mode_for_crtc(crtc->base.state, NULL) < 0);
 		crtc->base.state->active = crtc->active;
 		crtc->base.enabled = crtc->active;
+		crtc->base.state->connector_mask = 0;
 
 		/* Because we only establish the connector -> encoder ->
 		 * crtc links if something is active, this means the
@@ -15313,7 +15314,21 @@ static void intel_modeset_readout_hw_state(struct drm_device *dev)
 	for_each_intel_connector(dev, connector) {
 		if (connector->get_hw_state(connector)) {
 			connector->base.dpms = DRM_MODE_DPMS_ON;
-			connector->base.encoder = &connector->encoder->base;
+
+			encoder = connector->encoder;
+			connector->base.encoder = &encoder->base;
+
+			if (encoder->base.crtc &&
+			    encoder->base.crtc->state->active) {
+				/*
+				 * This has to be done during hardware readout
+				 * because anything calling .crtc_disable may
+				 * rely on the connector_mask being accurate.
+				 */
+				encoder->base.crtc->state->connector_mask |=
+					1 << drm_connector_index(&connector->base);
+			}
+
 		} else {
 			connector->base.dpms = DRM_MODE_DPMS_OFF;
 			connector->base.encoder = NULL;