X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fbacklight%2Fbacklight.c;h=4d94ebf58a7e30b6b5ed7ad345a5235336f52b8e;hb=d6bd972d061af306ede2affd2c9340a1660f7996;hp=691472cc3a9d9499b0de9af958c4434c223e28b2;hpb=0c9d8f1d4b5018199cb5a9b57580dc1480a7f915;p=elogind.git

diff --git a/src/backlight/backlight.c b/src/backlight/backlight.c
index 691472cc3..4d94ebf58 100644
--- a/src/backlight/backlight.c
+++ b/src/backlight/backlight.c
@@ -225,11 +225,13 @@ static unsigned get_max_brightness(struct udev_device *device) {
 
 /* Some systems turn the backlight all the way off at the lowest levels.
  * clamp_brightness clamps the saved brightness to at least 1 or 5% of
- * max_brightness.  This avoids preserving an unreadably dim screen, which
- * would otherwise force the user to disable state restoration. */
+ * max_brightness in case of 'backlight' subsystem. This avoids preserving
+ * an unreadably dim screen, which would otherwise force the user to
+ * disable state restoration. */
 static void clamp_brightness(struct udev_device *device, char **value, unsigned max_brightness) {
         int r;
         unsigned brightness, new_brightness, min_brightness;
+        const char *subsystem;
 
         r = safe_atou(*value, &brightness);
         if (r < 0) {
@@ -237,7 +239,12 @@ static void clamp_brightness(struct udev_device *device, char **value, unsigned
                 return;
         }
 
-        min_brightness = MAX(1U, max_brightness/20);
+        subsystem = udev_device_get_subsystem(device);
+        if (streq_ptr(subsystem, "backlight"))
+                min_brightness = MAX(1U, max_brightness/20);
+        else
+                min_brightness = 0;
+
         new_brightness = CLAMP(brightness, min_brightness, max_brightness);
         if (new_brightness != brightness) {
                 char *old_value = *value;