drm/crtc-helper: explicit DPMS on after modeset

danvet · airlied · commit 372835a8527f · 2013-06-25T11:01:30.000+10:00
Atm the crtc helper implementation of set_config has really inconsisten semantics: If just an fb update is good enough, dpms state will be left as-is, but if we do a full modeset we force everything to dpms on. This change has already been applied to the i915 modeset code in commit e3de42b Author: Imre Deak <imre.deak@intel.com> Date: Fri May 3 19:44:07 2013 +0200 drm/i915: force full modeset if the connector is in DPMS OFF mode which according to Greg KH seems to aim for a new record in most Bugzilla: links in a commit message. The history of this dpms forcing is pretty interesting. This patch here is an almost-revert of commit 811aaa5 Author: Keith Packard <keithp@keithp.com> Date: Thu Feb 3 16:57:28 2011 -0800 drm: Only set DPMS ON when actually configuring a mode which fixed the bug of trying to dpms on disabled outputs, but introduced the new discrepancy between an fb update only and full modesets. The actual introduction of this goes back to commit bf9dc10 Author: Keith Packard <keithp@keithp.com> Date: Fri Nov 26 10:45:58 2010 -0800 drm: Set connector DPMS status to ON in drm_crtc_helper_set_config And if you'd dig around in the i915 driver code there's even more fun around forcing dpms on and losing our heads and temper of the resulting inconsistencies. Especially the DP re-training code had tons of funny stuff in it. Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
@@ -754,12 +754,6 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
 				ret = -EINVAL;
 				goto fail;
 			}
-			DRM_DEBUG_KMS("Setting connector DPMS state to on\n");
-			for (i = 0; i < set->num_connectors; i++) {
-				DRM_DEBUG_KMS("\t[CONNECTOR:%d:%s] set DPMS on\n", set->connectors[i]->base.id,
-					      drm_get_connector_name(set->connectors[i]));
-				set->connectors[i]->funcs->dpms(set->connectors[i], DRM_MODE_DPMS_ON);
-			}
 		}
 		drm_helper_disable_unused_functions(dev);
 	} else if (fb_changed) {
@@ -777,6 +771,22 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
 		}
 	}
 
+	/*
+	 * crtc set_config helpers implicit set the crtc and all connected
+	 * encoders to DPMS on for a full mode set. But for just an fb update it
+	 * doesn't do that. To not confuse userspace, do an explicit DPMS_ON
+	 * unconditionally. This will also ensure driver internal dpms state is
+	 * consistent again.
+	 */
+	if (set->crtc->enabled) {
+		DRM_DEBUG_KMS("Setting connector DPMS state to on\n");
+		for (i = 0; i < set->num_connectors; i++) {
+			DRM_DEBUG_KMS("\t[CONNECTOR:%d:%s] set DPMS on\n", set->connectors[i]->base.id,
+				      drm_get_connector_name(set->connectors[i]));
+			set->connectors[i]->funcs->dpms(set->connectors[i], DRM_MODE_DPMS_ON);
+		}
+	}
+
 	kfree(save_connectors);
 	kfree(save_encoders);
 	kfree(save_crtcs);
