X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fbacklight%2Fbacklight.c;h=691472cc3a9d9499b0de9af958c4434c223e28b2;hb=865cc19a34cd9a3ff98a7b3754747f4904f56faa;hp=754a646c3d433690e1c334dfe823422abbaca7ea;hpb=938d2699d2e818bd996614e89ea3d668200ad2a8;p=elogind.git

diff --git a/src/backlight/backlight.c b/src/backlight/backlight.c
index 754a646c3..691472cc3 100644
--- a/src/backlight/backlight.c
+++ b/src/backlight/backlight.c
@@ -205,14 +205,18 @@ static unsigned get_max_brightness(struct udev_device *device) {
 
         max_brightness_str = udev_device_get_sysattr_value(device, "max_brightness");
         if (!max_brightness_str) {
-                log_warning("Failed to read 'max_brightness' attribute");
+                log_warning("Failed to read 'max_brightness' attribute.");
                 return 0;
         }
 
         r = safe_atou(max_brightness_str, &max_brightness);
         if (r < 0) {
-                log_warning("Failed to parse 'max_brightness' \"%s\": %s",
-                            max_brightness_str, strerror(-r));
+                log_warning("Failed to parse 'max_brightness' \"%s\": %s", max_brightness_str, strerror(-r));
+                return 0;
+        }
+
+        if (max_brightness <= 0) {
+                log_warning("Maximum brightness is 0, ignoring device.");
                 return 0;
         }
 
@@ -225,7 +229,7 @@ static unsigned get_max_brightness(struct udev_device *device) {
  * 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;
+        unsigned brightness, new_brightness, min_brightness;
 
         r = safe_atou(*value, &brightness);
         if (r < 0) {
@@ -233,7 +237,8 @@ static void clamp_brightness(struct udev_device *device, char **value, unsigned
                 return;
         }
 
-        new_brightness = MAX3(brightness, 1U, max_brightness/20);
+        min_brightness = MAX(1U, max_brightness/20);
+        new_brightness = CLAMP(brightness, min_brightness, max_brightness);
         if (new_brightness != brightness) {
                 char *old_value = *value;
 
@@ -243,7 +248,11 @@ static void clamp_brightness(struct udev_device *device, char **value, unsigned
                         return;
                 }
 
-                log_debug("Saved brightness %s too low; increasing to %s.", old_value, *value);
+                log_info("Saved brightness %s %s to %s.", old_value,
+                         new_brightness > brightness ?
+                         "too low; increasing" : "too high; decreasing",
+                         *value);
+
                 free(old_value);
         }
 }