| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| #include <unistd.h> |
| |
| #include "sd-device.h" |
| |
| #include "alloc-util.h" |
| #include "device-util.h" |
| #include "escape.h" |
| #include "fileio.h" |
| #include "main-func.h" |
| #include "mkdir.h" |
| #include "parse-util.h" |
| #include "pretty-print.h" |
| #include "process-util.h" |
| #include "reboot-util.h" |
| #include "string-util.h" |
| #include "strv.h" |
| #include "terminal-util.h" |
| |
| #define PCI_CLASS_GRAPHICS_CARD 0x30000 |
| |
| static int help(void) { |
| _cleanup_free_ char *link = NULL; |
| int r; |
| |
| r = terminal_urlify_man("systemd-backlight", "8", &link); |
| if (r < 0) |
| return log_oom(); |
| |
| printf("%s save [backlight|leds]:DEVICE\n" |
| "%s load [backlight|leds]:DEVICE\n" |
| "\n%sSave and restore backlight brightness at shutdown and boot.%s\n\n" |
| " save Save current brightness\n" |
| " load Set brightness to be the previously saved value\n" |
| "\nSee the %s for details.\n", |
| program_invocation_short_name, |
| program_invocation_short_name, |
| ansi_highlight(), |
| ansi_normal(), |
| link); |
| |
| return 0; |
| } |
| |
| static int has_multiple_graphics_cards(void) { |
| _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL; |
| sd_device *dev; |
| bool found = false; |
| int r; |
| |
| r = sd_device_enumerator_new(&e); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_enumerator_add_match_subsystem(e, "pci", /* match = */ true); |
| if (r < 0) |
| return r; |
| |
| /* class is an unsigned number, let's validate the value later. */ |
| r = sd_device_enumerator_add_match_sysattr(e, "class", NULL, /* match = */ true); |
| if (r < 0) |
| return r; |
| |
| FOREACH_DEVICE(e, dev) { |
| const char *s; |
| unsigned long c; |
| |
| if (sd_device_get_sysattr_value(dev, "class", &s) < 0) |
| continue; |
| |
| if (safe_atolu(s, &c) < 0) |
| continue; |
| |
| if (c != PCI_CLASS_GRAPHICS_CARD) |
| continue; |
| |
| if (found) |
| return true; /* This is the second device. */ |
| |
| found = true; /* Found the first device. */ |
| } |
| |
| return false; |
| } |
| |
| static int find_pci_or_platform_parent(sd_device *device, sd_device **ret) { |
| const char *subsystem, *sysname, *value; |
| sd_device *parent; |
| int r; |
| |
| assert(device); |
| assert(ret); |
| |
| r = sd_device_get_parent(device, &parent); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_get_subsystem(parent, &subsystem); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_get_sysname(parent, &sysname); |
| if (r < 0) |
| return r; |
| |
| if (streq(subsystem, "drm")) { |
| const char *c; |
| |
| c = startswith(sysname, "card"); |
| if (!c) |
| return -ENODATA; |
| |
| c += strspn(c, DIGITS); |
| if (*c == '-' && !STARTSWITH_SET(c, "-LVDS-", "-Embedded DisplayPort-", "-eDP-")) |
| /* A connector DRM device, let's ignore all but LVDS and eDP! */ |
| return -EOPNOTSUPP; |
| |
| } else if (streq(subsystem, "pci") && |
| sd_device_get_sysattr_value(parent, "class", &value) >= 0) { |
| unsigned long class; |
| |
| r = safe_atolu(value, &class); |
| if (r < 0) |
| return log_warning_errno(r, "Cannot parse PCI class '%s' of device %s:%s: %m", |
| value, subsystem, sysname); |
| |
| /* Graphics card */ |
| if (class == PCI_CLASS_GRAPHICS_CARD) { |
| *ret = parent; |
| return 0; |
| } |
| |
| } else if (streq(subsystem, "platform")) { |
| *ret = parent; |
| return 0; |
| } |
| |
| return find_pci_or_platform_parent(parent, ret); |
| } |
| |
| static int same_device(sd_device *a, sd_device *b) { |
| const char *a_val, *b_val; |
| int r; |
| |
| assert(a); |
| assert(b); |
| |
| r = sd_device_get_subsystem(a, &a_val); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_get_subsystem(b, &b_val); |
| if (r < 0) |
| return r; |
| |
| if (!streq(a_val, b_val)) |
| return false; |
| |
| r = sd_device_get_sysname(a, &a_val); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_get_sysname(b, &b_val); |
| if (r < 0) |
| return r; |
| |
| return streq(a_val, b_val); |
| } |
| |
| static int validate_device(sd_device *device) { |
| _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *enumerate = NULL; |
| const char *v, *sysname, *subsystem; |
| sd_device *parent, *other; |
| int r; |
| |
| 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. */ |
| |
| r = sd_device_get_sysname(device, &sysname); |
| if (r < 0) |
| return log_device_debug_errno(device, r, "Failed to get sysname: %m"); |
| |
| r = sd_device_get_subsystem(device, &subsystem); |
| if (r < 0) |
| return log_device_debug_errno(device, r, "Failed to get subsystem: %m"); |
| if (!streq(subsystem, "backlight")) |
| return true; |
| |
| r = sd_device_get_sysattr_value(device, "type", &v); |
| if (r < 0) |
| return log_device_debug_errno(device, r, "Failed to read 'type' sysattr: %m"); |
| if (!streq(v, "raw")) |
| return true; |
| |
| r = find_pci_or_platform_parent(device, &parent); |
| if (r < 0) |
| return log_device_debug_errno(device, r, "Failed to find PCI or platform parent: %m"); |
| |
| r = sd_device_get_subsystem(parent, &subsystem); |
| if (r < 0) |
| return log_device_debug_errno(parent, r, "Failed to get subsystem: %m"); |
| |
| if (DEBUG_LOGGING) { |
| const char *s = NULL; |
| |
| (void) sd_device_get_syspath(parent, &s); |
| log_device_debug(device, "Found %s parent device: %s", subsystem, strna(s)); |
| } |
| |
| r = sd_device_enumerator_new(&enumerate); |
| if (r < 0) |
| return log_oom_debug(); |
| |
| r = sd_device_enumerator_allow_uninitialized(enumerate); |
| if (r < 0) |
| return log_debug_errno(r, "Failed to allow uninitialized devices: %m"); |
| |
| r = sd_device_enumerator_add_match_subsystem(enumerate, "backlight", /* match = */ true); |
| if (r < 0) |
| return log_debug_errno(r, "Failed to add subsystem match: %m"); |
| |
| r = sd_device_enumerator_add_nomatch_sysname(enumerate, sysname); |
| if (r < 0) |
| return log_debug_errno(r, "Failed to add sysname unmatch: %m"); |
| |
| r = sd_device_enumerator_add_match_sysattr(enumerate, "type", "platform", /* match = */ true); |
| if (r < 0) |
| return log_debug_errno(r, "Failed to add sysattr match: %m"); |
| |
| r = sd_device_enumerator_add_match_sysattr(enumerate, "type", "firmware", /* match = */ true); |
| if (r < 0) |
| return log_debug_errno(r, "Failed to add sysattr match: %m"); |
| |
| if (streq(subsystem, "pci")) { |
| r = has_multiple_graphics_cards(); |
| if (r < 0) |
| return log_debug_errno(r, "Failed to check if the system has multiple graphics cards: %m"); |
| if (r > 0) { |
| /* If the system has multiple graphics cards, then we cannot associate platform |
| * devices on non-PCI bus (especially WMI bus) with PCI devices. Let's ignore all |
| * backlight devices that do not have the same parent PCI device. */ |
| log_debug("Found multiple graphics cards on PCI bus. " |
| "Skipping to associate platform backlight devices on non-PCI bus."); |
| |
| r = sd_device_enumerator_add_match_parent(enumerate, parent); |
| if (r < 0) |
| return log_debug_errno(r, "Failed to add parent match: %m"); |
| } |
| } |
| |
| FOREACH_DEVICE(enumerate, other) { |
| const char *other_subsystem; |
| sd_device *other_parent; |
| |
| /* OK, so there's another backlight device, and it's a platform or firmware device. |
| * Let's see if we can verify it belongs to the same device as ours. */ |
| r = find_pci_or_platform_parent(other, &other_parent); |
| if (r < 0) { |
| log_device_debug_errno(other, r, "Failed to get PCI or platform parent, ignoring: %m"); |
| continue; |
| } |
| |
| if (same_device(parent, other_parent) > 0) { |
| /* Both have the same PCI parent, that means we are out. */ |
| if (DEBUG_LOGGING) { |
| const char *other_sysname = NULL, *other_type = NULL; |
| |
| (void) sd_device_get_sysname(other, &other_sysname); |
| (void) sd_device_get_sysattr_value(other, "type", &other_type); |
| log_device_debug(device, |
| "Found another %s backlight device %s on the same PCI, skipping.", |
| strna(other_type), strna(other_sysname)); |
| } |
| return false; |
| } |
| |
| r = sd_device_get_subsystem(other_parent, &other_subsystem); |
| if (r < 0) { |
| log_device_debug_errno(other_parent, r, "Failed to get subsystem, ignoring: %m"); |
| continue; |
| } |
| |
| if (streq(other_subsystem, "platform") && streq(subsystem, "pci")) { |
| /* The other is connected to the platform bus and we are a PCI device, that also means we are out. */ |
| if (DEBUG_LOGGING) { |
| const char *other_sysname = NULL, *other_type = NULL; |
| |
| (void) sd_device_get_sysname(other, &other_sysname); |
| (void) sd_device_get_sysattr_value(other, "type", &other_type); |
| log_device_debug(device, |
| "Found another %s backlight device %s, which has higher precedence, skipping.", |
| strna(other_type), strna(other_sysname)); |
| } |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| static int get_max_brightness(sd_device *device, unsigned *ret) { |
| const char *s; |
| int r; |
| |
| assert(device); |
| assert(ret); |
| |
| r = sd_device_get_sysattr_value(device, "max_brightness", &s); |
| if (r < 0) |
| return log_device_warning_errno(device, r, "Failed to read 'max_brightness' attribute: %m"); |
| |
| r = safe_atou(s, ret); |
| if (r < 0) |
| return log_device_warning_errno(device, r, "Failed to parse 'max_brightness' \"%s\": %m", s); |
| |
| return 0; |
| } |
| |
| static int clamp_brightness(sd_device *device, bool saved, unsigned max_brightness, unsigned *brightness) { |
| unsigned new_brightness, min_brightness; |
| const char *subsystem; |
| int r; |
| |
| assert(device); |
| assert(brightness); |
| |
| /* Some systems turn the backlight all the way off at the lowest levels. This clamps the saved |
| * brightness to at least 1 or 5% of max_brightness in case of 'backlight' subsystem. This |
| * avoids preserving an unreadably dim screen, which would otherwise force the user to disable |
| * state restoration. */ |
| |
| r = sd_device_get_subsystem(device, &subsystem); |
| if (r < 0) |
| return log_device_warning_errno(device, r, "Failed to get device subsystem: %m"); |
| |
| if (streq(subsystem, "backlight")) |
| min_brightness = MAX(1U, max_brightness/20); |
| else |
| min_brightness = 0; |
| |
| new_brightness = CLAMP(*brightness, min_brightness, max_brightness); |
| if (new_brightness != *brightness) |
| log_device_info(device, "%s brightness %u is %s to %u.", |
| saved ? "Saved" : "Current", |
| *brightness, |
| new_brightness > *brightness ? |
| "too low; increasing" : "too high; decreasing", |
| new_brightness); |
| |
| *brightness = new_brightness; |
| return 0; |
| } |
| |
| static bool shall_clamp(sd_device *d) { |
| const char *s; |
| int r; |
| |
| assert(d); |
| |
| r = sd_device_get_property_value(d, "ID_BACKLIGHT_CLAMP", &s); |
| if (r < 0) { |
| if (r != -ENOENT) |
| log_device_debug_errno(d, r, "Failed to get ID_BACKLIGHT_CLAMP property, ignoring: %m"); |
| return true; |
| } |
| |
| r = parse_boolean(s); |
| if (r < 0) { |
| log_device_debug_errno(d, r, "Failed to parse ID_BACKLIGHT_CLAMP property, ignoring: %m"); |
| return true; |
| } |
| |
| return r; |
| } |
| |
| static int read_brightness(sd_device *device, unsigned max_brightness, unsigned *ret_brightness) { |
| const char *subsystem, *value; |
| unsigned brightness; |
| int r; |
| |
| assert(device); |
| assert(ret_brightness); |
| |
| r = sd_device_get_subsystem(device, &subsystem); |
| if (r < 0) |
| return log_device_debug_errno(device, r, "Failed to get subsystem: %m"); |
| |
| if (streq(subsystem, "backlight")) { |
| r = sd_device_get_sysattr_value(device, "actual_brightness", &value); |
| if (r == -ENOENT) { |
| log_device_debug_errno(device, r, "Failed to read 'actual_brightness' attribute, " |
| "fall back to use 'brightness' attribute: %m"); |
| goto use_brightness; |
| } |
| if (r < 0) |
| return log_device_debug_errno(device, r, "Failed to read 'actual_brightness' attribute: %m"); |
| |
| r = safe_atou(value, &brightness); |
| if (r < 0) { |
| log_device_debug_errno(device, r, "Failed to parse 'actual_brightness' attribute, " |
| "fall back to use 'brightness' attribute: %s", value); |
| goto use_brightness; |
| } |
| |
| if (brightness > max_brightness) { |
| log_device_debug(device, "actual_brightness=%u is larger than max_brightness=%u, " |
| "fall back to use 'brightness' attribute", brightness, max_brightness); |
| goto use_brightness; |
| } |
| |
| log_device_debug(device, "Current actual_brightness is %u", brightness); |
| *ret_brightness = brightness; |
| return 0; |
| } |
| |
| use_brightness: |
| r = sd_device_get_sysattr_value(device, "brightness", &value); |
| if (r < 0) |
| return log_device_debug_errno(device, r, "Failed to read 'brightness' attribute: %m"); |
| |
| r = safe_atou(value, &brightness); |
| if (r < 0) |
| return log_device_debug_errno(device, r, "Failed to parse 'brightness' attribute: %s", value); |
| |
| if (brightness > max_brightness) |
| return log_device_debug_errno(device, SYNTHETIC_ERRNO(EINVAL), |
| "brightness=%u is larger than max_brightness=%u", |
| brightness, max_brightness); |
| |
| log_device_debug(device, "Current brightness is %u", brightness); |
| *ret_brightness = brightness; |
| return 0; |
| } |
| |
| static int run(int argc, char *argv[]) { |
| _cleanup_(sd_device_unrefp) sd_device *device = NULL; |
| _cleanup_free_ char *escaped_ss = NULL, *escaped_sysname = NULL, *escaped_path_id = NULL; |
| const char *sysname, *path_id, *ss, *saved; |
| unsigned max_brightness, brightness; |
| int r; |
| |
| log_setup(); |
| |
| if (argv_looks_like_help(argc, argv)) |
| return help(); |
| |
| if (argc != 3) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "This program requires two arguments."); |
| |
| if (!STR_IN_SET(argv[1], "load", "save")) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Unknown verb %s.", argv[1]); |
| |
| umask(0022); |
| |
| r = mkdir_p("/var/lib/systemd/backlight", 0755); |
| if (r < 0) |
| return log_error_errno(r, "Failed to create backlight directory /var/lib/systemd/backlight: %m"); |
| |
| sysname = strchr(argv[2], ':'); |
| if (!sysname) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Requires a subsystem and sysname pair specifying a backlight device."); |
| |
| ss = strndupa_safe(argv[2], sysname - argv[2]); |
| |
| sysname++; |
| |
| if (!STR_IN_SET(ss, "backlight", "leds")) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Not a backlight or LED device: '%s:%s'", ss, sysname); |
| |
| r = sd_device_new_from_subsystem_sysname(&device, ss, sysname); |
| if (r < 0) { |
| bool ignore = r == -ENODEV; |
| |
| /* Some drivers, e.g. for AMD GPU, removes acpi backlight device soon after it is added. |
| * See issue #21997. */ |
| log_full_errno(ignore ? LOG_DEBUG : LOG_ERR, r, |
| "Failed to get backlight or LED device '%s:%s'%s: %m", |
| ss, sysname, ignore ? ", ignoring" : ""); |
| return ignore ? 0 : r; |
| } |
| |
| /* 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. */ |
| if (get_max_brightness(device, &max_brightness) < 0) |
| return 0; |
| |
| if (max_brightness == 0) { |
| log_device_warning(device, "Maximum brightness is 0, ignoring device."); |
| return 0; |
| } |
| |
| log_device_debug(device, "Maximum brightness is %u", max_brightness); |
| |
| escaped_ss = cescape(ss); |
| if (!escaped_ss) |
| return log_oom(); |
| |
| escaped_sysname = cescape(sysname); |
| if (!escaped_sysname) |
| return log_oom(); |
| |
| if (sd_device_get_property_value(device, "ID_PATH", &path_id) >= 0) { |
| escaped_path_id = cescape(path_id); |
| if (!escaped_path_id) |
| return log_oom(); |
| |
| saved = strjoina("/var/lib/systemd/backlight/", escaped_path_id, ":", escaped_ss, ":", escaped_sysname); |
| } else |
| saved = strjoina("/var/lib/systemd/backlight/", escaped_ss, ":", escaped_sysname); |
| |
| /* 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; |
| bool clamp; |
| |
| if (shall_restore_state() == 0) |
| return 0; |
| |
| if (validate_device(device) == 0) |
| return 0; |
| |
| clamp = shall_clamp(device); |
| |
| r = read_one_line_file(saved, &value); |
| if (r < 0 && r != -ENOENT) |
| return log_error_errno(r, "Failed to read %s: %m", saved); |
| if (r > 0) { |
| r = safe_atou(value, &brightness); |
| if (r < 0) { |
| log_warning_errno(r, "Failed to parse saved brightness '%s', removing %s.", |
| value, saved); |
| (void) unlink(saved); |
| } else { |
| log_debug("Using saved brightness %u.", brightness); |
| if (clamp) |
| (void) clamp_brightness(device, true, max_brightness, &brightness); |
| |
| /* Do not fall back to read current brightness below. */ |
| r = 1; |
| } |
| } |
| if (r <= 0) { |
| /* Fallback to clamping current brightness or exit early if clamping is not |
| * supported/enabled. */ |
| if (!clamp) |
| return 0; |
| |
| r = read_brightness(device, max_brightness, &brightness); |
| if (r < 0) |
| return log_device_error_errno(device, r, "Failed to read current brightness: %m"); |
| |
| (void) clamp_brightness(device, false, max_brightness, &brightness); |
| } |
| |
| r = sd_device_set_sysattr_valuef(device, "brightness", "%u", brightness); |
| if (r < 0) |
| return log_device_error_errno(device, r, "Failed to write system 'brightness' attribute: %m"); |
| |
| } else if (streq(argv[1], "save")) { |
| if (validate_device(device) == 0) { |
| (void) unlink(saved); |
| return 0; |
| } |
| |
| r = read_brightness(device, max_brightness, &brightness); |
| if (r < 0) |
| return log_device_error_errno(device, r, "Failed to read current brightness: %m"); |
| |
| r = write_string_filef(saved, WRITE_STRING_FILE_CREATE, "%u", brightness); |
| if (r < 0) |
| return log_device_error_errno(device, r, "Failed to write %s: %m", saved); |
| |
| } else |
| assert_not_reached(); |
| |
| return 0; |
| } |
| |
| DEFINE_MAIN_FUNCTION(run); |
