X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fbacklight%2Fbacklight.c;h=6c00b00d82c64e385948cf3a52139ddf69822c7f;hp=f22deed4e081970729859ec92cea4c6a4fe1c0e3;hb=295edddf5a2d884222a26935b40a4e99b924543d;hpb=1a0464230c08506c3fd715ff7cc56660df3a85ca
diff --git a/src/backlight/backlight.c b/src/backlight/backlight.c
index f22deed4e..6c00b00d8 100644
--- a/src/backlight/backlight.c
+++ b/src/backlight/backlight.c
@@ -19,16 +19,185 @@
along with systemd; If not, see .
***/
-#include
-
#include "util.h"
#include "mkdir.h"
#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;
+ const char *subsystem, *sysname;
+
+ assert(device);
+
+ parent = udev_device_get_parent(device);
+ if (!parent)
+ return NULL;
+
+ subsystem = udev_device_get_subsystem(parent);
+ if (!subsystem)
+ return NULL;
+
+ sysname = udev_device_get_sysname(parent);
+ if (!sysname)
+ return NULL;
+
+ if (streq(subsystem, "drm")) {
+ const char *c;
+
+ c = startswith(sysname, "card");
+ if (!c)
+ return NULL;
+
+ c += strspn(c, "0123456789");
+ if (*c == '-') {
+ /* A connector DRM device, let's ignore all but LVDS and eDP! */
+
+ if (!startswith(c, "-LVDS-") &&
+ !startswith(c, "-Embedded DisplayPort-"))
+ return NULL;
+ }
+
+ } else if (streq(subsystem, "pci")) {
+ const char *value;
+
+ value = udev_device_get_sysattr_value(parent, "class");
+ if (value) {
+ unsigned long class;
+
+ if (safe_atolu(value, &class) < 0) {
+ log_warning("Cannot parse PCI class %s of device %s:%s.", value, subsystem, sysname);
+ return NULL;
+ }
+
+ /* Graphics card */
+ if (class == 0x30000)
+ return parent;
+ }
+
+ } else if (streq(subsystem, "platform"))
+ return parent;
+
+ return find_pci_or_platform_parent(parent);
+}
+
+static bool same_device(struct udev_device *a, struct udev_device *b) {
+ assert(a);
+ assert(b);
+
+ if (!streq_ptr(udev_device_get_subsystem(a), udev_device_get_subsystem(b)))
+ return false;
+
+ if (!streq_ptr(udev_device_get_sysname(a), udev_device_get_sysname(b)))
+ return false;
+
+ return true;
+}
+
+static bool validate_device(struct udev *udev, struct udev_device *device) {
+ _cleanup_udev_enumerate_unref_ struct udev_enumerate *enumerate = NULL;
+ struct udev_list_entry *item = NULL, *first = NULL;
+ struct udev_device *parent;
+ const char *v, *subsystem;
+ int r;
+
+ assert(udev);
+ assert(device);
+
+ /* Verify whether we should actually care for a specific
+ * backlight device. For backlight devices there might be
+ * multiple ways to access the same control: "firmware"
+ * (i.e. ACPI), "platform" (i.e. via the machine's EC) and
+ * "raw" (via the graphics card). In general we should prefer
+ * "firmware" (i.e. ACPI) or "platform" access over "raw"
+ * access, in order not to confuse the BIOS/EC, and
+ * compatibility with possible low-level hotkey handling of
+ * screen brightness. The kernel will already make sure to
+ * expose only one of "firmware" and "platform" for the same
+ * device to userspace. However, we still need to make sure
+ * that we use "raw" only if no "firmware" or "platform"
+ * device for the same device exists. */
+
+ subsystem = udev_device_get_subsystem(device);
+ if (!streq_ptr(subsystem, "backlight"))
+ return true;
+
+ v = udev_device_get_sysattr_value(device, "type");
+ if (!streq_ptr(v, "raw"))
+ return true;
+
+ parent = find_pci_or_platform_parent(device);
+ if (!parent)
+ return true;
+
+ subsystem = udev_device_get_subsystem(parent);
+ if (!subsystem)
+ return true;
+
+ enumerate = udev_enumerate_new(udev);
+ if (!enumerate)
+ return true;
+
+ r = udev_enumerate_add_match_subsystem(enumerate, "backlight");
+ if (r < 0)
+ return true;
+
+ r = udev_enumerate_scan_devices(enumerate);
+ if (r < 0)
+ return true;
+
+ first = udev_enumerate_get_list_entry(enumerate);
+ udev_list_entry_foreach(item, first) {
+ _cleanup_udev_device_unref_ struct udev_device *other;
+ struct udev_device *other_parent;
+ const char *other_subsystem;
+
+ other = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
+ if (!other)
+ return true;
+
+ if (same_device(device, other))
+ continue;
+
+ v = udev_device_get_sysattr_value(other, "type");
+ if (!streq_ptr(v, "platform") && !streq_ptr(v, "firmware"))
+ continue;
+
+ /* OK, so there's another backlight device, and it's a
+ * platform or firmware device, so, let's see if we
+ * can verify it belongs to the same device as
+ * ours. */
+ other_parent = find_pci_or_platform_parent(other);
+ if (!other_parent)
+ continue;
+
+ if (same_device(parent, other_parent)) {
+ /* Both have the same PCI parent, that means
+ * we are out. */
+ 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));
+ return false;
+ }
+
+ other_subsystem = udev_device_get_subsystem(other_parent);
+ if (streq_ptr(other_subsystem, "platform") && streq_ptr(subsystem, "pci")) {
+ /* The other is connected to the platform bus
+ * and we are a PCI device, that also means we
+ * are out. */
+ 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));
+ return false;
+ }
+ }
+
+ return true;
+}
int main(int argc, char *argv[]) {
- struct udev *udev = NULL;
- struct udev_device *device = NULL;
- _cleanup_free_ char *saved = NULL;
+ _cleanup_udev_unref_ struct udev *udev = NULL;
+ _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;
int r;
if (argc != 3) {
@@ -45,91 +214,129 @@ int main(int argc, char *argv[]) {
r = mkdir_p("/var/lib/systemd/backlight", 0755);
if (r < 0) {
log_error("Failed to create backlight directory: %s", strerror(-r));
- goto finish;
+ return EXIT_FAILURE;
}
udev = udev_new();
if (!udev) {
- r = log_oom();
- goto finish;
+ log_oom();
+ return EXIT_FAILURE;
+ }
+
+ sysname = strchr(argv[2], ':');
+ if (!sysname) {
+ log_error("Requires pair of subsystem and sysname for specifying backlight device.");
+ return EXIT_FAILURE;
+ }
+
+ ss = strndup(argv[2], sysname - argv[2]);
+ if (!ss) {
+ log_oom();
+ return EXIT_FAILURE;
+ }
+
+ sysname++;
+
+ if (!streq(ss, "backlight") && !streq(ss, "leds")) {
+ log_error("Not a backlight or LED device: '%s:%s'", ss, sysname);
+ return EXIT_FAILURE;
}
errno = 0;
- device = udev_device_new_from_subsystem_sysname(udev, "backlight", argv[2]);
- if (!device)
- device = udev_device_new_from_subsystem_sysname(udev, "leds", argv[2]);
+ device = udev_device_new_from_subsystem_sysname(udev, ss, sysname);
if (!device) {
- if (errno != 0) {
- log_error("Failed to get backlight device '%s': %m", argv[2]);
- r = -errno;
- } else
- r = log_oom();
+ if (errno != 0)
+ log_error("Failed to get backlight or LED device '%s:%s': %m", ss, sysname);
+ else
+ log_oom();
+
+ return EXIT_FAILURE;
+ }
- goto finish;
+ escaped_ss = cescape(ss);
+ if (!escaped_ss) {
+ log_oom();
+ return EXIT_FAILURE;
}
- if (!streq_ptr(udev_device_get_subsystem(device), "backlight") &&
- !streq_ptr(udev_device_get_subsystem(device), "leds")) {
- log_error("Not a backlight device: %s", argv[2]);
- r = -ENODEV;
- goto finish;
+ escaped_sysname = cescape(sysname);
+ if (!escaped_sysname) {
+ log_oom();
+ return EXIT_FAILURE;
}
- saved = strappend("/var/lib/systemd/backlight/", udev_device_get_sysname(device));
+ path_id = udev_device_get_property_value(device, "ID_PATH");
+ if (path_id) {
+ escaped_path_id = cescape(path_id);
+ if (!escaped_path_id) {
+ log_oom();
+ return EXIT_FAILURE;
+ }
+
+ saved = strjoin("/var/lib/systemd/backlight/", escaped_path_id, ":", escaped_ss, ":", escaped_sysname, NULL);
+ } else
+ saved = strjoin("/var/lib/systemd/backlight/", escaped_ss, ":", escaped_sysname, NULL);
+
if (!saved) {
- r = log_oom();
- goto finish;
+ log_oom();
+ return EXIT_FAILURE;
}
- if (streq(argv[1], "load")) {
+ /* If there are multiple conflicting backlight devices, then
+ * 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
+ * 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()) {
_cleanup_free_ char *value = NULL;
+ if (!validate_device(udev, device))
+ return EXIT_SUCCESS;
+
r = read_one_line_file(saved, &value);
if (r < 0) {
- if (r == -ENOENT) {
- r = 0;
- goto finish;
- }
+ if (r == -ENOENT)
+ return EXIT_SUCCESS;
log_error("Failed to read %s: %s", saved, strerror(-r));
- goto finish;
+ return EXIT_FAILURE;
}
r = udev_device_set_sysattr_value(device, "brightness", value);
if (r < 0) {
log_error("Failed to write system attribute: %s", strerror(-r));
- goto finish;
+ return EXIT_FAILURE;
}
} else if (streq(argv[1], "save")) {
const char *value;
+ if (!validate_device(udev, device)) {
+ unlink(saved);
+ return EXIT_SUCCESS;
+ }
+
value = udev_device_get_sysattr_value(device, "brightness");
if (!value) {
log_error("Failed to read system attribute: %s", strerror(-r));
- goto finish;
+ return EXIT_FAILURE;
}
r = write_string_file(saved, value);
if (r < 0) {
log_error("Failed to write %s: %s", saved, strerror(-r));
- goto finish;
+ return EXIT_FAILURE;
}
} else {
log_error("Unknown verb %s.", argv[1]);
- r = -EINVAL;
- goto finish;
+ return EXIT_FAILURE;
}
-finish:
- if (device)
- udev_device_unref(device);
-
- if (udev)
- udev_unref(udev);
-
- return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
-
+ return EXIT_SUCCESS;
}