diff options
| -rw-r--r-- | src/backlight/backlight.c | 44 |
1 files changed, 30 insertions, 14 deletions
diff --git a/src/backlight/backlight.c b/src/backlight/backlight.c index abf8bcf00e..ce0385b08c 100644 --- a/src/backlight/backlight.c +++ b/src/backlight/backlight.c @@ -192,30 +192,37 @@ static bool validate_device(struct udev *udev, struct udev_device *device) { return true; } -/* 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. */ -static void clamp_brightness(struct udev_device *device, char **value) { +static unsigned get_max_brightness(struct udev_device *device) { int r; const char *max_brightness_str; - unsigned brightness, max_brightness, new_brightness; + unsigned max_brightness; max_brightness_str = udev_device_get_sysattr_value(device, "max_brightness"); if (!max_brightness_str) { - log_warning("Failed to read max_brightness attribute; not checking saved brightness"); - return; + log_warning("Failed to read max_brightness attribute"); + return 0; } - r = safe_atou(*value, &brightness); + r = safe_atou(max_brightness_str, &max_brightness); if (r < 0) { - log_warning("Failed to parse brightness \"%s\": %s", *value, strerror(-r)); - return; + log_warning("Failed to parse max_brightness \"%s\": %s", max_brightness_str, strerror(-r)); + return 0; } - r = safe_atou(max_brightness_str, &max_brightness); + return max_brightness; +} + +/* 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. */ +static void clamp_brightness(struct udev_device *device, char **value, unsigned max_brightness) { + int r; + unsigned brightness, new_brightness; + + r = safe_atou(*value, &brightness); if (r < 0) { - log_warning("Failed to parse max_brightness \"%s\": %s", max_brightness_str, strerror(-r)); + log_warning("Failed to parse brightness \"%s\": %s", *value, strerror(-r)); return; } @@ -239,6 +246,7 @@ int main(int argc, char *argv[]) { _cleanup_udev_device_unref_ struct udev_device *device = NULL; _cleanup_free_ char *saved = NULL, *ss = NULL, *escaped_ss = NULL, *escaped_sysname = NULL, *escaped_path_id = NULL; const char *sysname, *path_id; + unsigned max_brightness; int r; if (argc != 3) { @@ -294,6 +302,14 @@ int main(int argc, char *argv[]) { return EXIT_FAILURE; } + /* If max_brightness is 0, then there is no actual backlight + * device. This happens on desktops with Asus mainboards + * that load the eeepc-wmi module. + */ + max_brightness = get_max_brightness(device); + if (max_brightness == 0) + return EXIT_SUCCESS; + escaped_ss = cescape(ss); if (!escaped_ss) { log_oom(); @@ -348,7 +364,7 @@ int main(int argc, char *argv[]) { return EXIT_FAILURE; } - clamp_brightness(device, &value); + clamp_brightness(device, &value, max_brightness); r = udev_device_set_sysattr_value(device, "brightness", value); if (r < 0) { |