109 lines
4.5 KiB
Diff
109 lines
4.5 KiB
Diff
From 3cadce7d33e263ec7a6a83c00c11144930258b22 Mon Sep 17 00:00:00 2001
|
|
From: =?UTF-8?q?Thomas=20B=C3=A4chler?= <thomas@archlinux.org>
|
|
Date: Thu, 27 Mar 2014 23:41:59 +0100
|
|
Subject: [PATCH] backlight: do nothing if max_brightness is 0
|
|
|
|
On virtually any newer Asus mainboard, the eeepc-wmi driver is loaded.
|
|
It exposes a backlight device despite the lack of any physical backlight
|
|
devices. This fake backlight device has max_brightness set to 0. Since
|
|
the introduction of the clamp_brightness function, systemd-backlight
|
|
tries to write '1' to brightness and fails.
|
|
|
|
This patch changes systemd-backlight to exit gracefully when
|
|
max_brightness is 0 before performing any action. This affects
|
|
both the load and save actions.
|
|
---
|
|
src/backlight/backlight.c | 44 ++++++++++++++++++++++++++++++--------------
|
|
1 file changed, 30 insertions(+), 14 deletions(-)
|
|
|
|
diff --git src/backlight/backlight.c src/backlight/backlight.c
|
|
index abf8bcf..ce0385b 100644
|
|
--- src/backlight/backlight.c
|
|
+++ 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) {
|
|
--
|
|
1.7.9.2
|
|
|