Merge lp:~kaihengfeng/unity-settings-daemon/lp1683445 into lp:unity-settings-daemon

[Kai-Heng Feng]

[Kai-Heng Feng (kaihengfeng)]

Hi, this is still an issue for Unity users.
Can someone review this MP?

[Kai-Heng Feng (kaihengfeng)]

Another gentle ping...

[Robert Ancell (robert-ancell)]

I'm not familiar with this code but the patch makes sense to me.

review: Approve

[Robert Ancell (robert-ancell)]

Does this issue apply to gnome-settings-daemon i.e. for Ubuntu users in 18.04? The g-s-d code seems very different.

[Kai-Heng Feng (kaihengfeng)]

It's already fixed in GSD, and the fix was already back ported for 16.04.

The code should be the same as the GSD one [1].

In addition to Bionic, Xenial and Artful also need this fix.

[1] https://gitlab.gnome.org/GNOME/gnome-settings-daemon/commit/ed7c2744aca1ad0bdd5adb62a8f2b5bdc1eb94b4

=== modified file 'plugins/power/gsd-backlight-linux.c'
--- plugins/power/gsd-backlight-linux.c	2015-11-16 04:51:45 +0000
+++ plugins/power/gsd-backlight-linux.c	2017-05-10 08:46:43 +0000
@@ -41,6 +41,40 @@
 	}
 	return NULL;
 }
+
+/*
+ * Search for a raw backlight interface, raw backlight interfaces registered
+ * by the drm driver will have the drm-connector as their parent, check the
+ * drm-connector's enabled sysfs attribute so that we pick the right LCD-panel
+ * connector on laptops with hybrid-gfx. Fall back to just picking the first
+ * raw backlight interface if no enabled interface is found.
+ */
+static gchar *
+gsd_backlight_helper_get_raw (GList *devices)
+{
+	GUdevDevice *parent;
+	const gchar *attr;
+	GList *d;
+
+	for (d = devices; d != NULL; d = d->next) {
+		attr = g_udev_device_get_sysfs_attr (d->data, "type");
+		if (g_strcmp0 (attr, "raw") != 0)
+			continue;
+
+		parent = g_udev_device_get_parent (d->data);
+		if (!parent)
+			continue;
+
+		attr = g_udev_device_get_sysfs_attr (parent, "enabled");
+		if (!attr || g_strcmp0 (attr, "enabled") != 0)
+			continue;
+
+		return g_strdup (g_udev_device_get_sysfs_path (d->data));
+	}
+
+	return gsd_backlight_helper_get_type (devices, "raw");
+}
+
 #endif /* HAVE_GUDEV */
 
 char *
@@ -70,7 +104,7 @@
 			*type = GSD_BACKLIGHT_TYPE_PLATFORM;
 		goto out;
 	}
-	path = gsd_backlight_helper_get_type (devices, "raw");
+	path = gsd_backlight_helper_get_raw (devices);
 	if (path != NULL) {
 		if (type)
 			*type = GSD_BACKLIGHT_TYPE_RAW;