backlight: always prefer "firmware"/"platform" backlights over "raw" backlights if we have both for the same device
This commit is contained in:
Lennart Poettering
parent
124b48b00d
commit
0f4ba83c39
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@ -51,11 +51,11 @@ SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{ID_USB_INTERFACES}=="*:0701??:
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ACTION=="add", SUBSYSTEM=="net", KERNEL!="lo", RUN+="@rootlibexecdir@/systemd-sysctl --prefix=/proc/sys/net/ipv4/conf/$name --prefix=/proc/sys/net/ipv4/neigh/$name --prefix=/proc/sys/net/ipv6/conf/$name --prefix=/proc/sys/net/ipv6/neigh/$name"
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# Pull in backlight save/restore for all firmware backlight devices,
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# and keyboard backlights
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# Pull in backlight save/restore for all backlight devices and
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# keyboard backlights
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ACTION=="add", SUBSYSTEM=="backlight", ATTR{type}=="firmware", TAG+="systemd", ENV{SYSTEMD_WANTS}+="systemd-backlight@$name.service"
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ACTION=="add", SUBSYSTEM=="leds", KERNEL=="*kbd_backlight", TAG+="systemd", ENV{SYSTEMD_WANTS}+="systemd-backlight@$name.service"
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ACTION=="add", SUBSYSTEM=="backlight", TAG+="systemd", ENV{SYSTEMD_WANTS}+="systemd-backlight@backlight:$name.service"
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ACTION=="add", SUBSYSTEM=="leds", KERNEL=="*kbd_backlight", TAG+="systemd", ENV{SYSTEMD_WANTS}+="systemd-backlight@leds:$name.service"
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# Asynchronously mount file systems implemented by these modules as
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# soon as they are loaded.
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@ -25,10 +25,178 @@
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#include "libudev.h"
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#include "udev-util.h"
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static struct udev_device *find_pci_or_platform_parent(struct udev_device *device) {
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struct udev_device *parent;
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const char *subsystem, *sysname;
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assert(device);
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parent = udev_device_get_parent(device);
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if (!parent)
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return NULL;
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subsystem = udev_device_get_subsystem(parent);
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if (!subsystem)
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return NULL;
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sysname = udev_device_get_sysname(parent);
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if (!sysname)
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return NULL;
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if (streq(subsystem, "drm")) {
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const char *c;
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c = startswith(sysname, "card");
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if (!c)
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return NULL;
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c += strspn(c, "0123456789");
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if (*c == '-') {
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/* A connector DRM device, let's ignore all but LVDS and eDP! */
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if (!startswith(c, "-LVDS-") &&
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!startswith(c, "-Embedded DisplayPort-"))
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return NULL;
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}
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} else if (streq(subsystem, "pci")) {
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const char *value;
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value = udev_device_get_sysattr_value(parent, "class");
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if (value) {
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unsigned long class;
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if (safe_atolu(value, &class) < 0) {
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log_warning("Cannot parse PCI class %s of device %s:%s.", value, subsystem, sysname);
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return NULL;
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}
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/* Graphics card */
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if (class == 0x30000)
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return parent;
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}
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} else if (streq(subsystem, "platform"))
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return parent;
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return find_pci_or_platform_parent(parent);
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}
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static bool same_device(struct udev_device *a, struct udev_device *b) {
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assert(a);
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assert(b);
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if (!streq_ptr(udev_device_get_subsystem(a), udev_device_get_subsystem(b)))
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return false;
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if (!streq_ptr(udev_device_get_sysname(a), udev_device_get_sysname(b)))
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return false;
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return true;
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}
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static bool validate_device(struct udev *udev, struct udev_device *device) {
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_cleanup_udev_enumerate_unref_ struct udev_enumerate *enumerate = NULL;
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struct udev_list_entry *item = NULL, *first = NULL;
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struct udev_device *parent;
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const char *v, *subsystem;
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int r;
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assert(udev);
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assert(device);
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/* Verify whether we should actually care for a specific
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* backlight device. For backlight devices there might be
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* multiple ways to access the same control: "firmware"
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* (i.e. ACPI), "platform" (i.e. via the machine's EC) and
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* "raw" (via the graphics card). In general we should prefer
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* "firmware" (i.e. ACPI) or "platform" access over "raw"
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* access, in order not to confuse the BIOS/EC, and
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* compatibility with possible low-level hotkey handling of
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* screen brightness. The kernel will already make sure to
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* expose only one of "firmware" and "platform" for the same
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* device to userspace. However, we still need to make sure
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* that we use "raw" only if no "firmware" or "platform"
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* device for the same device exists. */
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subsystem = udev_device_get_subsystem(device);
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if (!streq_ptr(subsystem, "backlight"))
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return true;
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v = udev_device_get_sysattr_value(device, "type");
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if (!streq_ptr(v, "raw"))
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return true;
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parent = find_pci_or_platform_parent(device);
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if (!parent)
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return true;
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subsystem = udev_device_get_subsystem(parent);
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if (!subsystem)
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return true;
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enumerate = udev_enumerate_new(udev);
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if (!enumerate)
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return true;
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r = udev_enumerate_add_match_subsystem(enumerate, "backlight");
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if (r < 0)
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return true;
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r = udev_enumerate_scan_devices(enumerate);
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if (r < 0)
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return true;
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first = udev_enumerate_get_list_entry(enumerate);
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udev_list_entry_foreach(item, first) {
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_cleanup_udev_device_unref_ struct udev_device *other;
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struct udev_device *other_parent;
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const char *other_subsystem;
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other = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
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if (!other)
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return true;
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if (same_device(device, other))
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continue;
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v = udev_device_get_sysattr_value(other, "type");
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if (!streq_ptr(v, "platform") && !streq_ptr(v, "firmware"))
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continue;
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/* OK, so there's another backlight device, and it's a
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* platform or firmware device, so, let's see if we
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* can verify it belongs to the same device as
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* ours. */
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other_parent = find_pci_or_platform_parent(other);
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if (!other_parent)
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continue;
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if (same_device(parent, other_parent)) {
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/* Both have the same PCI parent, that means
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* we are out. */
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log_debug("Skipping backlight device %s, since backlight device %s is on same PCI device and, takes precedence.", udev_device_get_sysname(device), udev_device_get_sysname(other));
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return false;
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}
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other_subsystem = udev_device_get_subsystem(other_parent);
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if (streq_ptr(other_subsystem, "platform") && streq_ptr(subsystem, "pci")) {
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/* The other is connected to the platform bus
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* and we are a PCI device, that also means we
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* are out. */
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log_debug("Skipping backlight device %s, since backlight device %s is a platform device and takes precedence.", udev_device_get_sysname(device), udev_device_get_sysname(other));
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return false;
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}
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}
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return true;
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}
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int main(int argc, char *argv[]) {
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_cleanup_udev_unref_ struct udev *udev = NULL;
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_cleanup_udev_device_unref_ struct udev_device *device = NULL;
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_cleanup_free_ char *saved = NULL;
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_cleanup_free_ char *saved = NULL, *ss = NULL;
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const char *sysname;
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int r;
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if (argc != 3) {
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@ -54,34 +222,57 @@ int main(int argc, char *argv[]) {
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return EXIT_FAILURE;
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}
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sysname = strchr(argv[2], ':');
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if (!sysname) {
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log_error("Requires pair of subsystem and sysname for specifying backlight device.");
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return EXIT_FAILURE;
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}
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ss = strndup(argv[2], sysname - argv[2]);
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if (!ss) {
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log_oom();
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return EXIT_FAILURE;
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}
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sysname++;
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if (!streq(ss, "backlight") && !streq(ss, "leds")) {
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log_error("Not a backlight or LED device: '%s:%s'", ss, sysname);
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return EXIT_FAILURE;
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}
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errno = 0;
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device = udev_device_new_from_subsystem_sysname(udev, "backlight", argv[2]);
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if (!device)
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device = udev_device_new_from_subsystem_sysname(udev, "leds", argv[2]);
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device = udev_device_new_from_subsystem_sysname(udev, ss, sysname);
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if (!device) {
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if (errno != 0)
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log_error("Failed to get backlight device '%s': %m", argv[2]);
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log_error("Failed to get backlight or LED device '%s:%s': %m", ss, sysname);
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else
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r = log_oom();
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log_oom();
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return EXIT_FAILURE;
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}
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if (!streq_ptr(udev_device_get_subsystem(device), "backlight") &&
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!streq_ptr(udev_device_get_subsystem(device), "leds")) {
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log_error("Not a backlight device: %s", argv[2]);
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return EXIT_FAILURE;
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}
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saved = strappend("/var/lib/systemd/backlight/", udev_device_get_sysname(device));
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saved = strjoin("/var/lib/systemd/backlight/", ss, ":", sysname, NULL);
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if (!saved) {
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log_oom();
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return EXIT_FAILURE;
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}
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/* If there are multiple conflicting backlight devices, then
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* their probing at boot-time might happen in any order. This
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* means the validity checking of the device then is not
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* reliable, since it might not see other devices conflicting
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* with a specific backlight. To deal with this we will
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* actively delete backlight state files at shutdown (where
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* device probing should be complete), so that the validity
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* check at boot time doesn't have to be reliable. */
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if (streq(argv[1], "load")) {
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_cleanup_free_ char *value = NULL;
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if (!validate_device(udev, device))
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return EXIT_SUCCESS;
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r = read_one_line_file(saved, &value);
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if (r < 0) {
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@ -101,6 +292,11 @@ int main(int argc, char *argv[]) {
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} else if (streq(argv[1], "save")) {
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const char *value;
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if (!validate_device(udev, device)) {
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unlink(saved);
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return EXIT_SUCCESS;
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}
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value = udev_device_get_sysattr_value(device, "brightness");
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if (!value) {
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log_error("Failed to read system attribute: %s", strerror(-r));
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