| /* SPDX-License-Identifier: LGPL-2.1+ */ |
| |
| #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 "proc-cmdline.h" |
| #include "string-util.h" |
| #include "strv.h" |
| #include "util.h" |
| |
| 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 == '-') { |
| /* A connector DRM device, let's ignore all but LVDS and eDP! */ |
| if (!STARTSWITH_SET(c, "-LVDS-", "-Embedded DisplayPort-")) |
| return -EOPNOTSUPP; |
| } |
| |
| } else if (streq(subsystem, "pci") && |
| sd_device_get_sysattr_value(parent, "class", &value) >= 0) { |
| unsigned long class = 0; |
| |
| 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 == 0x30000) { |
| *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, *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_subsystem(device, &subsystem); |
| if (r < 0) |
| return r; |
| if (!streq(subsystem, "backlight")) |
| return true; |
| |
| r = sd_device_get_sysattr_value(device, "type", &v); |
| if (r < 0) |
| return r; |
| if (!streq(v, "raw")) |
| return true; |
| |
| r = find_pci_or_platform_parent(device, &parent); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_get_subsystem(parent, &subsystem); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_enumerator_new(&enumerate); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_enumerator_allow_uninitialized(enumerate); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_enumerator_add_match_subsystem(enumerate, "backlight", true); |
| if (r < 0) |
| return r; |
| |
| FOREACH_DEVICE(enumerate, other) { |
| const char *other_subsystem; |
| sd_device *other_parent; |
| |
| if (same_device(device, other) > 0) |
| continue; |
| |
| if (sd_device_get_sysattr_value(other, "type", &v) < 0 || |
| !STR_IN_SET(v, "platform", "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. */ |
| if (find_pci_or_platform_parent(other, &other_parent) < 0) |
| continue; |
| |
| if (same_device(parent, other_parent)) { |
| const char *device_sysname = NULL, *other_sysname = NULL; |
| |
| /* Both have the same PCI parent, that means we are out. */ |
| |
| (void) sd_device_get_sysname(device, &device_sysname); |
| (void) sd_device_get_sysname(other, &other_sysname); |
| |
| log_debug("Skipping backlight device %s, since device %s is on same PCI device and takes precedence.", |
| device_sysname, other_sysname); |
| return false; |
| } |
| |
| if (sd_device_get_subsystem(other_parent, &other_subsystem) < 0) |
| continue; |
| |
| if (streq(other_subsystem, "platform") && streq(subsystem, "pci")) { |
| const char *device_sysname = NULL, *other_sysname = NULL; |
| |
| /* The other is connected to the platform bus and we are a PCI device, that also means we are out. */ |
| |
| (void) sd_device_get_sysname(device, &device_sysname); |
| (void) sd_device_get_sysname(other, &other_sysname); |
| |
| log_debug("Skipping backlight device %s, since device %s is a platform device and takes precedence.", |
| device_sysname, other_sysname); |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| static int get_max_brightness(sd_device *device, unsigned *ret) { |
| const char *max_brightness_str; |
| unsigned max_brightness; |
| int r; |
| |
| assert(device); |
| assert(ret); |
| |
| r = sd_device_get_sysattr_value(device, "max_brightness", &max_brightness_str); |
| if (r < 0) |
| return log_device_warning_errno(device, r, "Failed to read 'max_brightness' attribute: %m"); |
| |
| r = safe_atou(max_brightness_str, &max_brightness); |
| if (r < 0) |
| return log_device_warning_errno(device, r, "Failed to parse 'max_brightness' \"%s\": %m", max_brightness_str); |
| |
| if (max_brightness <= 0) { |
| log_device_warning(device, "Maximum brightness is 0, ignoring device."); |
| return -EINVAL; |
| } |
| |
| *ret = max_brightness; |
| return 0; |
| } |
| |
| /* 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 in case of 'backlight' subsystem. This avoids preserving |
| * an unreadably dim screen, which would otherwise force the user to |
| * disable state restoration. */ |
| static int clamp_brightness(sd_device *device, char **value, unsigned max_brightness) { |
| unsigned brightness, new_brightness, min_brightness; |
| const char *subsystem; |
| int r; |
| |
| assert(value); |
| assert(*value); |
| |
| r = safe_atou(*value, &brightness); |
| if (r < 0) |
| return log_device_warning_errno(device, r, "Failed to parse brightness \"%s\": %m", *value); |
| |
| 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) { |
| char *new_value; |
| |
| r = asprintf(&new_value, "%u", new_brightness); |
| if (r < 0) |
| return log_oom(); |
| |
| log_device_info(device, "Saved brightness %s %s to %s.", *value, |
| new_brightness > brightness ? |
| "too low; increasing" : "too high; decreasing", |
| new_value); |
| |
| free_and_replace(*value, new_value); |
| } |
| |
| 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) { |
| 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 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; |
| int r; |
| |
| if (argc != 3) { |
| log_error("This program requires two arguments."); |
| return -EINVAL; |
| } |
| |
| log_setup_service(); |
| |
| 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) { |
| log_error("Requires a subsystem and sysname pair specifying a backlight device."); |
| return -EINVAL; |
| } |
| |
| ss = strndupa(argv[2], sysname - argv[2]); |
| |
| sysname++; |
| |
| if (!STR_IN_SET(ss, "backlight", "leds")) { |
| log_error("Not a backlight or LED device: '%s:%s'", ss, sysname); |
| return -EINVAL; |
| } |
| |
| r = sd_device_new_from_subsystem_sysname(&device, ss, sysname); |
| if (r < 0) |
| return log_error_errno(r, "Failed to get backlight or LED device '%s:%s': %m", ss, sysname); |
| |
| /* 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; |
| |
| 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 (IN_SET(r, -ENOENT, 0)) { |
| const char *curval; |
| |
| /* Fallback to clamping current brightness or exit early if |
| * clamping is not supported/enabled. */ |
| if (!clamp) |
| return 0; |
| |
| r = sd_device_get_sysattr_value(device, "brightness", &curval); |
| if (r < 0) |
| return log_device_warning_errno(device, r, "Failed to read 'brightness' attribute: %m"); |
| |
| value = strdup(curval); |
| if (!value) |
| return log_oom(); |
| } else if (r < 0) |
| return log_error_errno(r, "Failed to read %s: %m", saved); |
| |
| if (clamp) |
| (void) clamp_brightness(device, &value, max_brightness); |
| |
| r = sd_device_set_sysattr_value(device, "brightness", value); |
| if (r < 0) |
| return log_device_error_errno(device, r, "Failed to write system 'brightness' attribute: %m"); |
| |
| } else if (streq(argv[1], "save")) { |
| const char *value; |
| |
| if (validate_device(device) == 0) { |
| (void) unlink(saved); |
| return 0; |
| } |
| |
| r = sd_device_get_sysattr_value(device, "brightness", &value); |
| if (r < 0) |
| return log_device_error_errno(device, r, "Failed to read system 'brightness' attribute: %m"); |
| |
| r = write_string_file(saved, value, WRITE_STRING_FILE_CREATE); |
| if (r < 0) |
| return log_device_error_errno(device, r, "Failed to write %s: %m", saved); |
| |
| } else { |
| log_error("Unknown verb %s.", argv[1]); |
| return -EINVAL; |
| } |
| |
| return 0; |
| } |
| |
| DEFINE_MAIN_FUNCTION(run); |