From 041baf4c40f45d3f3cc56645edfc6f3433c66047 Mon Sep 17 00:00:00 2001
From: David Herrmann <dh.herrmann@googlemail.com>
Date: Sat, 12 Jan 2013 14:01:01 +0100
Subject: [PATCH] uterm: drm: reread dpms state on wakeup

Other DRM users might change the DPMS state of a display while we are
asleep. Therefore, reread the state during wakeup and force DPMS to the
same value it had when we left. But do this only for displays that are
online, other displays are never touched by uterm-video.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
---
 src/uterm_drm_shared.c          | 51 +++++++++++++++++++++------------
 src/uterm_drm_shared_internal.h |  2 +-
 2 files changed, 34 insertions(+), 19 deletions(-)

diff --git a/src/uterm_drm_shared.c b/src/uterm_drm_shared.c
index 90069de..d97f139 100644
--- a/src/uterm_drm_shared.c
+++ b/src/uterm_drm_shared.c
@@ -458,14 +458,15 @@ err_unref:
 }
 
 int uterm_drm_video_hotplug(struct uterm_video *video,
-			    const struct display_ops *ops)
+			    const struct display_ops *ops,
+			    bool read_dpms)
 {
 	struct uterm_drm_video *vdrm = video->data;
 	drmModeRes *res;
 	drmModeConnector *conn;
 	struct uterm_display *disp;
 	struct uterm_drm_display *ddrm;
-	int i;
+	int i, dpms;
 	struct shl_dlist *iter, *tmp;
 
 	if (!video_is_awake(video) || !video_need_hotplug(video))
@@ -486,21 +487,35 @@ int uterm_drm_video_hotplug(struct uterm_video *video,
 		conn = drmModeGetConnector(vdrm->fd, res->connectors[i]);
 		if (!conn)
 			continue;
-		if (conn->connection == DRM_MODE_CONNECTED) {
-			shl_dlist_for_each(iter, &video->displays) {
-				disp = shl_dlist_entry(iter,
-						       struct uterm_display,
-						       list);
-				ddrm = disp->data;
-
-				if (ddrm->conn_id == res->connectors[i]) {
-					disp->flags |= DISPLAY_AVAILABLE;
-					break;
-				}
-			}
-			if (iter == &video->displays)
-				bind_display(video, res, conn, ops);
+		if (conn->connection != DRM_MODE_CONNECTED) {
+			drmModeFreeConnector(conn);
+			continue;
 		}
+
+		shl_dlist_for_each(iter, &video->displays) {
+			disp = shl_dlist_entry(iter, struct uterm_display,
+					       list);
+			ddrm = disp->data;
+
+			if (ddrm->conn_id != res->connectors[i])
+				continue;
+
+			disp->flags |= DISPLAY_AVAILABLE;
+			if (!read_dpms || !display_is_online(disp))
+				break;
+
+			dpms = uterm_drm_get_dpms(vdrm->fd, conn);
+			if (dpms != disp->dpms) {
+				log_debug("DPMS state for display %p changed",
+					  disp);
+				uterm_drm_display_set_dpms(disp, disp->dpms);
+			}
+			break;
+		}
+
+		if (iter == &video->displays)
+			bind_display(video, res, conn, ops);
+
 		drmModeFreeConnector(conn);
 	}
 
@@ -529,7 +544,7 @@ int uterm_drm_video_wake_up(struct uterm_video *video,
 	}
 
 	video->flags |= VIDEO_AWAKE;
-	ret = uterm_drm_video_hotplug(video, ops);
+	ret = uterm_drm_video_hotplug(video, ops, true);
 	if (ret) {
 		drmDropMaster(vdrm->fd);
 		return ret;
@@ -549,5 +564,5 @@ int uterm_drm_video_poll(struct uterm_video *video,
 			 const struct display_ops *ops)
 {
 	video->flags |= VIDEO_HOTPLUG;
-	return uterm_drm_video_hotplug(video, ops);
+	return uterm_drm_video_hotplug(video, ops, false);
 }
diff --git a/src/uterm_drm_shared_internal.h b/src/uterm_drm_shared_internal.h
index 199d5b3..fc92b6f 100644
--- a/src/uterm_drm_shared_internal.h
+++ b/src/uterm_drm_shared_internal.h
@@ -103,7 +103,7 @@ void uterm_drm_video_destroy(struct uterm_video *video);
 int uterm_drm_video_find_crtc(struct uterm_video *video, drmModeRes *res,
 			      drmModeEncoder *enc);
 int uterm_drm_video_hotplug(struct uterm_video *video,
-			    const struct display_ops *ops);
+			    const struct display_ops *ops, bool read_dpms);
 int uterm_drm_video_wake_up(struct uterm_video *video,
 			    const struct display_ops *ops);
 void uterm_drm_video_sleep(struct uterm_video *video);