diff options
Diffstat (limited to 'src/backlight')
| -rw-r--r-- | src/backlight/backlight.c | 222 |
1 files changed, 209 insertions, 13 deletions
diff --git a/src/backlight/backlight.c b/src/backlight/backlight.c index c45b2d0b6b..51a67a042a 100644 --- a/src/backlight/backlight.c +++ b/src/backlight/backlight.c @@ -25,10 +25,178 @@ #include "libudev.h" #include "udev-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[]) { _cleanup_udev_unref_ struct udev *udev = NULL; _cleanup_udev_device_unref_ struct udev_device *device = NULL; - _cleanup_free_ char *saved = NULL; + _cleanup_free_ char *saved = NULL, *ss = NULL; + const char *sysname; int r; if (argc != 3) { @@ -54,34 +222,57 @@ int main(int argc, char *argv[]) { 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]); + log_error("Failed to get backlight or LED device '%s:%s': %m", ss, sysname); else - r = log_oom(); - - return EXIT_FAILURE; - } + log_oom(); - 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]); return EXIT_FAILURE; } - saved = strappend("/var/lib/systemd/backlight/", udev_device_get_sysname(device)); + saved = strjoin("/var/lib/systemd/backlight/", ss, ":", sysname, NULL); if (!saved) { log_oom(); return EXIT_FAILURE; } + /* 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")) { _cleanup_free_ char *value = NULL; + if (!validate_device(udev, device)) + return EXIT_SUCCESS; + r = read_one_line_file(saved, &value); if (r < 0) { @@ -101,6 +292,11 @@ int main(int argc, char *argv[]) { } 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)); |