#include "fileio.h"
#include "libudev.h"
#include "udev-util.h"
-#include "util.h"
static struct udev_device *find_pci_or_platform_parent(struct udev_device *device) {
struct udev_device *parent;
value = udev_device_get_sysattr_value(parent, "class");
if (value) {
- unsigned long class;
+ unsigned long class = 0;
if (safe_atolu(value, &class) < 0) {
log_warning("Cannot parse PCI class %s of device %s:%s.", value, subsystem, sysname);
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) {
+ int r;
+ const char *max_brightness_str;
+ unsigned brightness, max_brightness, new_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;
+ }
+
+ r = safe_atou(*value, &brightness);
+ if (r < 0) {
+ log_warning("Failed to parse brightness \"%s\": %s", *value, strerror(-r));
+ return;
+ }
+
+ 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));
+ return;
+ }
+
+ new_brightness = MAX3(brightness, 1U, max_brightness/20);
+ if (new_brightness != brightness) {
+ char *old_value = *value;
+
+ r = asprintf(value, "%u", new_brightness);
+ if (r < 0) {
+ log_oom();
+ return;
+ }
+
+ log_debug("Saved brightness %s too low; increasing to %s.", old_value, *value);
+ free(old_value);
+ }
+}
+
int main(int argc, char *argv[]) {
_cleanup_udev_unref_ struct udev *udev = NULL;
_cleanup_udev_device_unref_ struct udev_device *device = NULL;
* their probing at boot-time might happen in any order. This
* means the validity checking of the device then is not
* reliable, since it might not see other devices conflicting
- * with a specific backlight. To deal with this we will
+ * with a specific backlight. To deal with this, we will
* actively delete backlight state files at shutdown (where
* device probing should be complete), so that the validity
* check at boot time doesn't have to be reliable. */
- if (streq(argv[1], "load") && restore_state()) {
+ if (streq(argv[1], "load") && shall_restore_state()) {
_cleanup_free_ char *value = NULL;
if (!validate_device(udev, device))
return EXIT_FAILURE;
}
+ clamp_brightness(device, &value);
+
r = udev_device_set_sysattr_value(device, "brightness", value);
if (r < 0) {
log_error("Failed to write system attribute: %s", strerror(-r));
value = udev_device_get_sysattr_value(device, "brightness");
if (!value) {
- log_error("Failed to read system attribute: %s", strerror(-r));
+ log_error("Failed to read system attribute");
return EXIT_FAILURE;
}