[gnome-settings-daemon] power: Add backlight_available() function

[Bastien Nocera <hadess src gnome org>]

commit f79d8b32641da31d5190c25c65b61f21f96f9ce5
Author: Bastien Nocera <hadess hadess net>
Date:   Wed Jan 23 23:45:17 2013 +0100

    power: Add backlight_available() function
    
    Checking both the XRandR backlight functionality and udev for a suitable
    backlight.

 configure.ac               |    2 +-
 plugins/power/Makefile.am  |    4 ++++
 plugins/power/gpm-common.c |   18 ++++++++++++++++++
 plugins/power/gpm-common.h |    1 +
 4 files changed, 24 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index dcf5983..116ce68 100644
--- a/configure.ac
+++ b/configure.ac
@@ -234,7 +234,7 @@ PKG_CHECK_MODULES(SOUND, [libpulse >= $PA_REQUIRED_VERSION $GUDEV_PKG libpulse-m
 # ---------------------------------------------------------------------------
 # Power
 # ---------------------------------------------------------------------------
-PKG_CHECK_MODULES(POWER, upower-glib >= $UPOWER_REQUIRED_VERSION gnome-desktop-3.0 >= $GNOME_DESKTOP_REQUIRED_VERSION libcanberra-gtk3 libnotify x11 xext xtst)
+PKG_CHECK_MODULES(POWER, upower-glib >= $UPOWER_REQUIRED_VERSION gnome-desktop-3.0 >= $GNOME_DESKTOP_REQUIRED_VERSION $GUDEV_PKG libcanberra-gtk3 libnotify x11 xext xtst)
 
 if test x$have_gudev != xno; then
 	PKG_CHECK_MODULES(BACKLIGHT_HELPER,
diff --git a/plugins/power/Makefile.am b/plugins/power/Makefile.am
index 371e8ba..a33cbc5 100644
--- a/plugins/power/Makefile.am
+++ b/plugins/power/Makefile.am
@@ -8,6 +8,8 @@ plugin_LTLIBRARIES =					\
 libpower_la_SOURCES = 					\
 	gpm-common.c					\
 	gpm-common.h					\
+	gsd-backlight-linux.c				\
+	gsd-backlight-linux.h				\
 	gsd-power-manager.c				\
 	gsd-power-manager.h				\
 	gsm-inhibitor-flag.h				\
@@ -63,6 +65,8 @@ libexec_PROGRAMS = gsd-test-power
 gsd_test_power_SOURCES =				\
 	gpm-common.c					\
 	gpm-common.h					\
+	gsd-backlight-linux.c				\
+	gsd-backlight-linux.h				\
 	gsd-power-manager.c				\
 	gsd-power-manager.h				\
 	gsm-inhibitor-flag.h				\
diff --git a/plugins/power/gpm-common.c b/plugins/power/gpm-common.c
index 2fcb0d2..1c20234 100644
--- a/plugins/power/gpm-common.c
+++ b/plugins/power/gpm-common.c
@@ -35,6 +35,7 @@
 
 #include "gpm-common.h"
 #include "gsd-power-manager.h"
+#include "gsd-backlight-linux.h"
 
 #define XSCREENSAVER_WATCHDOG_TIMEOUT           120 /* seconds */
 
@@ -1190,6 +1191,23 @@ backlight_helper_disabled (void)
         return FALSE;
 }
 
+gboolean
+backlight_available (GnomeRRScreen *rr_screen)
+{
+        char *path;
+
+        if (!backlight_helper_disabled ())
+                return FALSE;
+        if (get_primary_output (rr_screen) != NULL)
+                return TRUE;
+        path = gsd_backlight_helper_get_best_backlight ();
+        if (path == NULL)
+                return FALSE;
+
+        g_free (path);
+        return TRUE;
+}
+
 /**
  * backlight_helper_get_value:
  *
diff --git a/plugins/power/gpm-common.h b/plugins/power/gpm-common.h
index b03b5b5..b5f544c 100644
--- a/plugins/power/gpm-common.h
+++ b/plugins/power/gpm-common.h
@@ -54,6 +54,7 @@ void             reset_idletime                         (void);
 #define PERCENTAGE_TO_ABS(min, max, value) (min + (((max - min) * value) / 100))
 
 int              gsd_power_backlight_abs_to_percentage  (int min, int max, int value);
+gboolean         backlight_available                    (GnomeRRScreen *rr_screen);
 int              backlight_get_abs                      (GnomeRRScreen *rr_screen, GError **error);
 int              backlight_get_percentage               (GnomeRRScreen *rr_screen, GError **error);
 int              backlight_get_min                      (GnomeRRScreen *rr_screen);