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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
3731acf1 LP |
2 | /*** |
3 | This file is part of systemd. | |
4 | ||
5 | Copyright 2013 Lennart Poettering | |
6 | ||
7 | systemd is free software; you can redistribute it and/or modify it | |
8 | under the terms of the GNU Lesser General Public License as published by | |
9 | the Free Software Foundation; either version 2.1 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | systemd is distributed in the hope that it will be useful, but | |
13 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | Lesser General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU Lesser General Public License | |
18 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
19 | ***/ | |
20 | ||
b4bbcaa9 TA |
21 | #include "libudev.h" |
22 | ||
b5efdb8a | 23 | #include "alloc-util.h" |
4f5dd394 LP |
24 | #include "def.h" |
25 | #include "escape.h" | |
3731acf1 | 26 | #include "fileio.h" |
4f5dd394 | 27 | #include "mkdir.h" |
4e731273 LP |
28 | #include "parse-util.h" |
29 | #include "proc-cmdline.h" | |
07630cea | 30 | #include "string-util.h" |
1ca208fb | 31 | #include "udev-util.h" |
4f5dd394 | 32 | #include "util.h" |
3731acf1 | 33 | |
0f4ba83c LP |
34 | static struct udev_device *find_pci_or_platform_parent(struct udev_device *device) { |
35 | struct udev_device *parent; | |
36 | const char *subsystem, *sysname; | |
37 | ||
38 | assert(device); | |
39 | ||
40 | parent = udev_device_get_parent(device); | |
41 | if (!parent) | |
42 | return NULL; | |
43 | ||
44 | subsystem = udev_device_get_subsystem(parent); | |
45 | if (!subsystem) | |
46 | return NULL; | |
47 | ||
48 | sysname = udev_device_get_sysname(parent); | |
49 | if (!sysname) | |
50 | return NULL; | |
51 | ||
52 | if (streq(subsystem, "drm")) { | |
53 | const char *c; | |
54 | ||
55 | c = startswith(sysname, "card"); | |
56 | if (!c) | |
57 | return NULL; | |
58 | ||
938d2699 | 59 | c += strspn(c, DIGITS); |
0f4ba83c LP |
60 | if (*c == '-') { |
61 | /* A connector DRM device, let's ignore all but LVDS and eDP! */ | |
62 | ||
63 | if (!startswith(c, "-LVDS-") && | |
64 | !startswith(c, "-Embedded DisplayPort-")) | |
65 | return NULL; | |
66 | } | |
67 | ||
68 | } else if (streq(subsystem, "pci")) { | |
69 | const char *value; | |
70 | ||
71 | value = udev_device_get_sysattr_value(parent, "class"); | |
72 | if (value) { | |
39883f62 | 73 | unsigned long class = 0; |
0f4ba83c LP |
74 | |
75 | if (safe_atolu(value, &class) < 0) { | |
938d2699 ZJS |
76 | log_warning("Cannot parse PCI class %s of device %s:%s.", |
77 | value, subsystem, sysname); | |
0f4ba83c LP |
78 | return NULL; |
79 | } | |
80 | ||
81 | /* Graphics card */ | |
82 | if (class == 0x30000) | |
83 | return parent; | |
84 | } | |
85 | ||
86 | } else if (streq(subsystem, "platform")) | |
87 | return parent; | |
88 | ||
89 | return find_pci_or_platform_parent(parent); | |
90 | } | |
91 | ||
92 | static bool same_device(struct udev_device *a, struct udev_device *b) { | |
93 | assert(a); | |
94 | assert(b); | |
95 | ||
96 | if (!streq_ptr(udev_device_get_subsystem(a), udev_device_get_subsystem(b))) | |
97 | return false; | |
98 | ||
99 | if (!streq_ptr(udev_device_get_sysname(a), udev_device_get_sysname(b))) | |
100 | return false; | |
101 | ||
102 | return true; | |
103 | } | |
104 | ||
105 | static bool validate_device(struct udev *udev, struct udev_device *device) { | |
106 | _cleanup_udev_enumerate_unref_ struct udev_enumerate *enumerate = NULL; | |
107 | struct udev_list_entry *item = NULL, *first = NULL; | |
108 | struct udev_device *parent; | |
109 | const char *v, *subsystem; | |
110 | int r; | |
111 | ||
112 | assert(udev); | |
113 | assert(device); | |
114 | ||
115 | /* Verify whether we should actually care for a specific | |
116 | * backlight device. For backlight devices there might be | |
117 | * multiple ways to access the same control: "firmware" | |
118 | * (i.e. ACPI), "platform" (i.e. via the machine's EC) and | |
119 | * "raw" (via the graphics card). In general we should prefer | |
120 | * "firmware" (i.e. ACPI) or "platform" access over "raw" | |
121 | * access, in order not to confuse the BIOS/EC, and | |
122 | * compatibility with possible low-level hotkey handling of | |
123 | * screen brightness. The kernel will already make sure to | |
124 | * expose only one of "firmware" and "platform" for the same | |
125 | * device to userspace. However, we still need to make sure | |
126 | * that we use "raw" only if no "firmware" or "platform" | |
127 | * device for the same device exists. */ | |
128 | ||
129 | subsystem = udev_device_get_subsystem(device); | |
130 | if (!streq_ptr(subsystem, "backlight")) | |
131 | return true; | |
132 | ||
133 | v = udev_device_get_sysattr_value(device, "type"); | |
134 | if (!streq_ptr(v, "raw")) | |
135 | return true; | |
136 | ||
137 | parent = find_pci_or_platform_parent(device); | |
138 | if (!parent) | |
139 | return true; | |
140 | ||
141 | subsystem = udev_device_get_subsystem(parent); | |
142 | if (!subsystem) | |
143 | return true; | |
144 | ||
145 | enumerate = udev_enumerate_new(udev); | |
146 | if (!enumerate) | |
147 | return true; | |
148 | ||
149 | r = udev_enumerate_add_match_subsystem(enumerate, "backlight"); | |
150 | if (r < 0) | |
151 | return true; | |
152 | ||
153 | r = udev_enumerate_scan_devices(enumerate); | |
154 | if (r < 0) | |
155 | return true; | |
156 | ||
157 | first = udev_enumerate_get_list_entry(enumerate); | |
158 | udev_list_entry_foreach(item, first) { | |
159 | _cleanup_udev_device_unref_ struct udev_device *other; | |
160 | struct udev_device *other_parent; | |
161 | const char *other_subsystem; | |
162 | ||
163 | other = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)); | |
164 | if (!other) | |
165 | return true; | |
166 | ||
167 | if (same_device(device, other)) | |
168 | continue; | |
169 | ||
170 | v = udev_device_get_sysattr_value(other, "type"); | |
1cf03a4f | 171 | if (!STRPTR_IN_SET(v, "platform", "firmware")) |
0f4ba83c LP |
172 | continue; |
173 | ||
174 | /* OK, so there's another backlight device, and it's a | |
175 | * platform or firmware device, so, let's see if we | |
176 | * can verify it belongs to the same device as | |
177 | * ours. */ | |
178 | other_parent = find_pci_or_platform_parent(other); | |
179 | if (!other_parent) | |
180 | continue; | |
181 | ||
182 | if (same_device(parent, other_parent)) { | |
183 | /* Both have the same PCI parent, that means | |
184 | * we are out. */ | |
938d2699 ZJS |
185 | log_debug("Skipping backlight device %s, since device %s is on same PCI device and takes precedence.", |
186 | udev_device_get_sysname(device), | |
187 | udev_device_get_sysname(other)); | |
0f4ba83c LP |
188 | return false; |
189 | } | |
190 | ||
191 | other_subsystem = udev_device_get_subsystem(other_parent); | |
192 | if (streq_ptr(other_subsystem, "platform") && streq_ptr(subsystem, "pci")) { | |
193 | /* The other is connected to the platform bus | |
194 | * and we are a PCI device, that also means we | |
195 | * are out. */ | |
938d2699 ZJS |
196 | log_debug("Skipping backlight device %s, since device %s is a platform device and takes precedence.", |
197 | udev_device_get_sysname(device), | |
198 | udev_device_get_sysname(other)); | |
0f4ba83c LP |
199 | return false; |
200 | } | |
201 | } | |
202 | ||
203 | return true; | |
204 | } | |
205 | ||
3cadce7d | 206 | static unsigned get_max_brightness(struct udev_device *device) { |
7b909d74 JT |
207 | int r; |
208 | const char *max_brightness_str; | |
3cadce7d | 209 | unsigned max_brightness; |
7b909d74 JT |
210 | |
211 | max_brightness_str = udev_device_get_sysattr_value(device, "max_brightness"); | |
212 | if (!max_brightness_str) { | |
c7fdf44d | 213 | log_warning("Failed to read 'max_brightness' attribute."); |
3cadce7d | 214 | return 0; |
7b909d74 JT |
215 | } |
216 | ||
3cadce7d | 217 | r = safe_atou(max_brightness_str, &max_brightness); |
7b909d74 | 218 | if (r < 0) { |
da927ba9 | 219 | log_warning_errno(r, "Failed to parse 'max_brightness' \"%s\": %m", max_brightness_str); |
c7fdf44d LP |
220 | return 0; |
221 | } | |
222 | ||
223 | if (max_brightness <= 0) { | |
224 | log_warning("Maximum brightness is 0, ignoring device."); | |
3cadce7d | 225 | return 0; |
7b909d74 JT |
226 | } |
227 | ||
3cadce7d TB |
228 | return max_brightness; |
229 | } | |
230 | ||
231 | /* Some systems turn the backlight all the way off at the lowest levels. | |
232 | * clamp_brightness clamps the saved brightness to at least 1 or 5% of | |
4cd2b2cf DT |
233 | * max_brightness in case of 'backlight' subsystem. This avoids preserving |
234 | * an unreadably dim screen, which would otherwise force the user to | |
235 | * disable state restoration. */ | |
3cadce7d TB |
236 | static void clamp_brightness(struct udev_device *device, char **value, unsigned max_brightness) { |
237 | int r; | |
0c9d8f1d | 238 | unsigned brightness, new_brightness, min_brightness; |
4cd2b2cf | 239 | const char *subsystem; |
3cadce7d TB |
240 | |
241 | r = safe_atou(*value, &brightness); | |
7b909d74 | 242 | if (r < 0) { |
da927ba9 | 243 | log_warning_errno(r, "Failed to parse brightness \"%s\": %m", *value); |
7b909d74 JT |
244 | return; |
245 | } | |
246 | ||
4cd2b2cf DT |
247 | subsystem = udev_device_get_subsystem(device); |
248 | if (streq_ptr(subsystem, "backlight")) | |
249 | min_brightness = MAX(1U, max_brightness/20); | |
250 | else | |
251 | min_brightness = 0; | |
252 | ||
0c9d8f1d | 253 | new_brightness = CLAMP(brightness, min_brightness, max_brightness); |
7b909d74 JT |
254 | if (new_brightness != brightness) { |
255 | char *old_value = *value; | |
256 | ||
257 | r = asprintf(value, "%u", new_brightness); | |
258 | if (r < 0) { | |
259 | log_oom(); | |
260 | return; | |
261 | } | |
262 | ||
0c9d8f1d JN |
263 | log_info("Saved brightness %s %s to %s.", old_value, |
264 | new_brightness > brightness ? | |
265 | "too low; increasing" : "too high; decreasing", | |
266 | *value); | |
267 | ||
7b909d74 JT |
268 | free(old_value); |
269 | } | |
270 | } | |
271 | ||
3731acf1 | 272 | int main(int argc, char *argv[]) { |
1ca208fb ZJS |
273 | _cleanup_udev_unref_ struct udev *udev = NULL; |
274 | _cleanup_udev_device_unref_ struct udev_device *device = NULL; | |
be3f52f4 LP |
275 | _cleanup_free_ char *saved = NULL, *ss = NULL, *escaped_ss = NULL, *escaped_sysname = NULL, *escaped_path_id = NULL; |
276 | const char *sysname, *path_id; | |
3cadce7d | 277 | unsigned max_brightness; |
3731acf1 LP |
278 | int r; |
279 | ||
280 | if (argc != 3) { | |
281 | log_error("This program requires two arguments."); | |
282 | return EXIT_FAILURE; | |
283 | } | |
284 | ||
285 | log_set_target(LOG_TARGET_AUTO); | |
286 | log_parse_environment(); | |
287 | log_open(); | |
288 | ||
289 | umask(0022); | |
290 | ||
ef5bfcf6 | 291 | r = mkdir_p("/var/lib/systemd/backlight", 0755); |
3731acf1 | 292 | if (r < 0) { |
c33b3297 | 293 | log_error_errno(r, "Failed to create backlight directory /var/lib/systemd/backlight: %m"); |
1ca208fb | 294 | return EXIT_FAILURE; |
3731acf1 LP |
295 | } |
296 | ||
297 | udev = udev_new(); | |
298 | if (!udev) { | |
1ca208fb ZJS |
299 | log_oom(); |
300 | return EXIT_FAILURE; | |
3731acf1 LP |
301 | } |
302 | ||
0f4ba83c LP |
303 | sysname = strchr(argv[2], ':'); |
304 | if (!sysname) { | |
938d2699 | 305 | log_error("Requires a subsystem and sysname pair specifying a backlight device."); |
0f4ba83c LP |
306 | return EXIT_FAILURE; |
307 | } | |
308 | ||
309 | ss = strndup(argv[2], sysname - argv[2]); | |
310 | if (!ss) { | |
311 | log_oom(); | |
312 | return EXIT_FAILURE; | |
313 | } | |
314 | ||
315 | sysname++; | |
316 | ||
317 | if (!streq(ss, "backlight") && !streq(ss, "leds")) { | |
318 | log_error("Not a backlight or LED device: '%s:%s'", ss, sysname); | |
319 | return EXIT_FAILURE; | |
320 | } | |
321 | ||
875c6e1b | 322 | errno = 0; |
0f4ba83c | 323 | device = udev_device_new_from_subsystem_sysname(udev, ss, sysname); |
3731acf1 | 324 | if (!device) { |
b3267152 | 325 | if (errno > 0) |
56f64d95 | 326 | log_error_errno(errno, "Failed to get backlight or LED device '%s:%s': %m", ss, sysname); |
1ca208fb | 327 | else |
0f4ba83c | 328 | log_oom(); |
3731acf1 | 329 | |
1ca208fb | 330 | return EXIT_FAILURE; |
3731acf1 LP |
331 | } |
332 | ||
3cadce7d TB |
333 | /* If max_brightness is 0, then there is no actual backlight |
334 | * device. This happens on desktops with Asus mainboards | |
335 | * that load the eeepc-wmi module. | |
336 | */ | |
337 | max_brightness = get_max_brightness(device); | |
338 | if (max_brightness == 0) | |
339 | return EXIT_SUCCESS; | |
340 | ||
be3f52f4 LP |
341 | escaped_ss = cescape(ss); |
342 | if (!escaped_ss) { | |
343 | log_oom(); | |
344 | return EXIT_FAILURE; | |
345 | } | |
346 | ||
347 | escaped_sysname = cescape(sysname); | |
348 | if (!escaped_sysname) { | |
349 | log_oom(); | |
350 | return EXIT_FAILURE; | |
351 | } | |
352 | ||
353 | path_id = udev_device_get_property_value(device, "ID_PATH"); | |
354 | if (path_id) { | |
355 | escaped_path_id = cescape(path_id); | |
356 | if (!escaped_path_id) { | |
357 | log_oom(); | |
358 | return EXIT_FAILURE; | |
359 | } | |
360 | ||
605405c6 | 361 | saved = strjoin("/var/lib/systemd/backlight/", escaped_path_id, ":", escaped_ss, ":", escaped_sysname); |
be3f52f4 | 362 | } else |
605405c6 | 363 | saved = strjoin("/var/lib/systemd/backlight/", escaped_ss, ":", escaped_sysname); |
be3f52f4 | 364 | |
3731acf1 | 365 | if (!saved) { |
1ca208fb ZJS |
366 | log_oom(); |
367 | return EXIT_FAILURE; | |
3731acf1 LP |
368 | } |
369 | ||
0f4ba83c LP |
370 | /* If there are multiple conflicting backlight devices, then |
371 | * their probing at boot-time might happen in any order. This | |
372 | * means the validity checking of the device then is not | |
373 | * reliable, since it might not see other devices conflicting | |
73e231ab | 374 | * with a specific backlight. To deal with this, we will |
0f4ba83c LP |
375 | * actively delete backlight state files at shutdown (where |
376 | * device probing should be complete), so that the validity | |
377 | * check at boot time doesn't have to be reliable. */ | |
378 | ||
b76388e1 | 379 | if (streq(argv[1], "load")) { |
3731acf1 | 380 | _cleanup_free_ char *value = NULL; |
bca81be7 | 381 | const char *clamp; |
3731acf1 | 382 | |
934ae16b | 383 | if (shall_restore_state() == 0) |
b76388e1 MB |
384 | return EXIT_SUCCESS; |
385 | ||
0f4ba83c LP |
386 | if (!validate_device(udev, device)) |
387 | return EXIT_SUCCESS; | |
388 | ||
3731acf1 LP |
389 | r = read_one_line_file(saved, &value); |
390 | if (r < 0) { | |
391 | ||
1ca208fb ZJS |
392 | if (r == -ENOENT) |
393 | return EXIT_SUCCESS; | |
3731acf1 | 394 | |
da927ba9 | 395 | log_error_errno(r, "Failed to read %s: %m", saved); |
1ca208fb | 396 | return EXIT_FAILURE; |
3731acf1 LP |
397 | } |
398 | ||
bca81be7 TM |
399 | clamp = udev_device_get_property_value(device, "ID_BACKLIGHT_CLAMP"); |
400 | if (!clamp || parse_boolean(clamp) != 0) /* default to clamping */ | |
401 | clamp_brightness(device, &value, max_brightness); | |
7b909d74 | 402 | |
3731acf1 LP |
403 | r = udev_device_set_sysattr_value(device, "brightness", value); |
404 | if (r < 0) { | |
c33b3297 | 405 | log_error_errno(r, "Failed to write system 'brightness' attribute: %m"); |
1ca208fb | 406 | return EXIT_FAILURE; |
3731acf1 LP |
407 | } |
408 | ||
409 | } else if (streq(argv[1], "save")) { | |
410 | const char *value; | |
411 | ||
0f4ba83c LP |
412 | if (!validate_device(udev, device)) { |
413 | unlink(saved); | |
414 | return EXIT_SUCCESS; | |
415 | } | |
416 | ||
3731acf1 LP |
417 | value = udev_device_get_sysattr_value(device, "brightness"); |
418 | if (!value) { | |
938d2699 | 419 | log_error("Failed to read system 'brightness' attribute"); |
1ca208fb | 420 | return EXIT_FAILURE; |
3731acf1 LP |
421 | } |
422 | ||
4c1fc3e4 | 423 | r = write_string_file(saved, value, WRITE_STRING_FILE_CREATE); |
3731acf1 | 424 | if (r < 0) { |
da927ba9 | 425 | log_error_errno(r, "Failed to write %s: %m", saved); |
1ca208fb | 426 | return EXIT_FAILURE; |
3731acf1 LP |
427 | } |
428 | ||
429 | } else { | |
430 | log_error("Unknown verb %s.", argv[1]); | |
1ca208fb | 431 | return EXIT_FAILURE; |
3731acf1 LP |
432 | } |
433 | ||
1ca208fb | 434 | return EXIT_SUCCESS; |
3731acf1 | 435 | } |