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_errno(r, "Failed to parse 'max_brightness' \"%s\": %m", max_brightness_str);
+ return 0;
+ }
+
+ if (max_brightness <= 0) {
+ log_warning("Maximum brightness is 0, ignoring device.");
return 0;
}
/* 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;
+ unsigned brightness, new_brightness, min_brightness;
+ const char *subsystem;
r = safe_atou(*value, &brightness);
if (r < 0) {
- log_warning("Failed to parse brightness \"%s\": %s", *value, strerror(-r));
+ log_warning_errno(r, "Failed to parse brightness \"%s\": %m", *value);
return;
}
- new_brightness = MAX3(brightness, 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;
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);
}
}
r = mkdir_p("/var/lib/systemd/backlight", 0755);
if (r < 0) {
- log_error("Failed to create backlight directory /var/lib/systemd/backlight: %s",
- strerror(-r));
+ log_error_errno(r, "Failed to create backlight directory /var/lib/systemd/backlight: %m");
return EXIT_FAILURE;
}
device = udev_device_new_from_subsystem_sysname(udev, ss, sysname);
if (!device) {
if (errno != 0)
- log_error("Failed to get backlight or LED device '%s:%s': %m", ss, sysname);
+ log_error_errno(errno, "Failed to get backlight or LED device '%s:%s': %m", ss, sysname);
else
log_oom();
* device probing should be complete), so that the validity
* check at boot time doesn't have to be reliable. */
- if (streq(argv[1], "load") && shall_restore_state()) {
+ if (streq(argv[1], "load")) {
_cleanup_free_ char *value = NULL;
+ if (!shall_restore_state())
+ return EXIT_SUCCESS;
+
if (!validate_device(udev, device))
return EXIT_SUCCESS;
if (r == -ENOENT)
return EXIT_SUCCESS;
- log_error("Failed to read %s: %s", saved, strerror(-r));
+ log_error_errno(r, "Failed to read %s: %m", saved);
return EXIT_FAILURE;
}
r = udev_device_set_sysattr_value(device, "brightness", value);
if (r < 0) {
- log_error("Failed to write system 'brightness' attribute: %s",
- strerror(-r));
+ log_error_errno(r, "Failed to write system 'brightness' attribute: %m");
return EXIT_FAILURE;
}
r = write_string_file(saved, value);
if (r < 0) {
- log_error("Failed to write %s: %s", saved, strerror(-r));
+ log_error_errno(r, "Failed to write %s: %m", saved);
return EXIT_FAILURE;
}