aboutsummaryrefslogtreecommitdiffstats
path: root/src/loader/loader.c
blob: fc468153425029916c68d9ce2d9ab13a689c64ed (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
/*
 * Copyright (C) 2013 Rob Clark <robclark@freedesktop.org>
 *
 * This code is derived from the following files.
 *
 * * src/glx/dri3_common.c
 * Copyright © 2013 Keith Packard
 *
 * * src/egl/drivers/dri2/common.c
 * * src/gbm/backends/dri/driver_name.c
 * Copyright © 2011 Intel Corporation
 *
 * Authors:
 *    Kristian Høgsberg <krh@bitplanet.net>
 *    Benjamin Franzke <benjaminfranzke@googlemail.com>
 *
 * * src/gallium/targets/egl-static/egl.c
 * Copyright (C) 2010-2011 LunarG Inc.
 *
 * Authors:
 *    Chia-I Wu <olv@lunarg.com>
 *
 * * src/gallium/state_trackers/egl/drm/native_drm.c
 * Copyright (C) 2010 Chia-I Wu <olv@0xlab.org>
 *
 * * src/egl/drivers/dri2/platform_android.c
 *
 * Copyright (C) 2010-2011 Chia-I Wu <olvaffe@gmail.com>
 * Copyright (C) 2010-2011 LunarG Inc.
 *
 * Based on platform_x11, which has
 *
 * Copyright © 2011 Intel Corporation
 *
 * * src/gallium/auxiliary/pipe-loader/pipe_loader_drm.c
 * Copyright 2011 Intel Corporation
 * Copyright 2012 Francisco Jerez
 * All Rights Reserved.
 *
 * Authors:
 *    Kristian Høgsberg <krh@bitplanet.net>
 *    Benjamin Franzke <benjaminfranzke@googlemail.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * Authors:
 *    Rob Clark <robclark@freedesktop.org>
 */

#include <sys/stat.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#ifdef HAVE_LIBUDEV
#include <assert.h>
#include <dlfcn.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#ifdef USE_DRICONF
#include "xmlconfig.h"
#include "xmlpool.h"
#endif
#endif
#ifdef HAVE_SYSFS
#include <sys/types.h>
#endif
#include "loader.h"

#ifndef __NOT_HAVE_DRM_H
#include <xf86drm.h>
#endif

#define __IS_LOADER
#include "pci_id_driver_map.h"

static void default_logger(int level, const char *fmt, ...)
{
   if (level <= _LOADER_WARNING) {
      va_list args;
      va_start(args, fmt);
      vfprintf(stderr, fmt, args);
      va_end(args);
   }
}

static void (*log_)(int level, const char *fmt, ...) = default_logger;

#ifdef HAVE_LIBUDEV
#include <libudev.h>

static void *udev_handle = NULL;

static void *
udev_dlopen_handle(void)
{
   if (!udev_handle) {
      udev_handle = dlopen("libudev.so.1", RTLD_LOCAL | RTLD_LAZY);

      if (!udev_handle) {
         /* libudev.so.1 changed the return types of the two unref functions
          * from voids to pointers.  We don't use those return values, and the
          * only ABI I've heard that cares about this kind of change (calling
          * a function with a void * return that actually only returns void)
          * might be ia64.
          */
         udev_handle = dlopen("libudev.so.0", RTLD_LOCAL | RTLD_LAZY);

         if (!udev_handle) {
            log_(_LOADER_WARNING, "Couldn't dlopen libudev.so.1 or "
                 "libudev.so.0, driver detection may be broken.\n");
         }
      }
   }

   return udev_handle;
}

static int dlsym_failed = 0;

static void *
checked_dlsym(void *dlopen_handle, const char *name)
{
   void *result = dlsym(dlopen_handle, name);
   if (!result)
      dlsym_failed = 1;
   return result;
}

#define UDEV_SYMBOL(ret, name, args) \
   ret (*name) args = checked_dlsym(udev_dlopen_handle(), #name);


static inline struct udev_device *
udev_device_new_from_fd(struct udev *udev, int fd)
{
   struct udev_device *device;
   struct stat buf;
   UDEV_SYMBOL(struct udev_device *, udev_device_new_from_devnum,
               (struct udev *udev, char type, dev_t devnum));

   if (dlsym_failed)
      return NULL;

   if (fstat(fd, &buf) < 0) {
      log_(_LOADER_WARNING, "MESA-LOADER: failed to stat fd %d\n", fd);
      return NULL;
   }

   device = udev_device_new_from_devnum(udev, 'c', buf.st_rdev);
   if (device == NULL) {
      log_(_LOADER_WARNING,
              "MESA-LOADER: could not create udev device for fd %d\n", fd);
      return NULL;
   }

   return device;
}

static int
libudev_get_pci_id_for_fd(int fd, int *vendor_id, int *chip_id)
{
   struct udev *udev = NULL;
   struct udev_device *device = NULL, *parent;
   const char *pci_id;
   UDEV_SYMBOL(struct udev *, udev_new, (void));
   UDEV_SYMBOL(struct udev_device *, udev_device_get_parent,
               (struct udev_device *));
   UDEV_SYMBOL(const char *, udev_device_get_property_value,
               (struct udev_device *, const char *));
   UDEV_SYMBOL(struct udev_device *, udev_device_unref,
               (struct udev_device *));
   UDEV_SYMBOL(struct udev *, udev_unref, (struct udev *));

   *chip_id = -1;

   if (dlsym_failed)
      return 0;

   udev = udev_new();
   device = udev_device_new_from_fd(udev, fd);
   if (!device)
      goto out;

   parent = udev_device_get_parent(device);
   if (parent == NULL) {
      log_(_LOADER_WARNING, "MESA-LOADER: could not get parent device\n");
      goto out;
   }

   pci_id = udev_device_get_property_value(parent, "PCI_ID");
   if (pci_id == NULL) {
      log_(_LOADER_INFO, "MESA-LOADER: no PCI ID\n");
      *chip_id = -1;
      goto out;
   } else if (sscanf(pci_id, "%x:%x", vendor_id, chip_id) != 2) {
      log_(_LOADER_WARNING, "MESA-LOADER: malformed PCI ID\n");
      *chip_id = -1;
      goto out;
   }

out:
   if (device)
      udev_device_unref(device);
   if (udev)
      udev_unref(udev);

   return (*chip_id >= 0);
}

static char *
get_render_node_from_id_path_tag(struct udev *udev,
                                 char *id_path_tag,
                                 char another_tag)
{
   struct udev_device *device;
   struct udev_enumerate *e;
   struct udev_list_entry *entry;
   const char *path, *id_path_tag_tmp;
   char *path_res;
   char found = 0;
   UDEV_SYMBOL(struct udev_enumerate *, udev_enumerate_new,
               (struct udev *));
   UDEV_SYMBOL(int, udev_enumerate_add_match_subsystem,
               (struct udev_enumerate *, const char *));
   UDEV_SYMBOL(int, udev_enumerate_add_match_sysname,
               (struct udev_enumerate *, const char *));
   UDEV_SYMBOL(int, udev_enumerate_scan_devices,
               (struct udev_enumerate *));
   UDEV_SYMBOL(struct udev_list_entry *, udev_enumerate_get_list_entry,
               (struct udev_enumerate *));
   UDEV_SYMBOL(struct udev_list_entry *, udev_list_entry_get_next,
               (struct udev_list_entry *));
   UDEV_SYMBOL(const char *, udev_list_entry_get_name,
               (struct udev_list_entry *));
   UDEV_SYMBOL(struct udev_device *, udev_device_new_from_syspath,
               (struct udev *, const char *));
   UDEV_SYMBOL(const char *, udev_device_get_property_value,
               (struct udev_device *, const char *));
   UDEV_SYMBOL(const char *, udev_device_get_devnode,
               (struct udev_device *));
   UDEV_SYMBOL(struct udev_device *, udev_device_unref,
               (struct udev_device *));

   e = udev_enumerate_new(udev);
   udev_enumerate_add_match_subsystem(e, "drm");
   udev_enumerate_add_match_sysname(e, "render*");

   udev_enumerate_scan_devices(e);
   udev_list_entry_foreach(entry, udev_enumerate_get_list_entry(e)) {
      path = udev_list_entry_get_name(entry);
      device = udev_device_new_from_syspath(udev, path);
      if (!device)
         continue;
      id_path_tag_tmp = udev_device_get_property_value(device, "ID_PATH_TAG");
      if (id_path_tag_tmp) {
         if ((!another_tag && !strcmp(id_path_tag, id_path_tag_tmp)) ||
             (another_tag && strcmp(id_path_tag, id_path_tag_tmp))) {
            found = 1;
            break;
         }
      }
      udev_device_unref(device);
   }

   if (found) {
      path_res = strdup(udev_device_get_devnode(device));
      udev_device_unref(device);
      return path_res;
   }
   return NULL;
}

static char *
get_id_path_tag_from_fd(struct udev *udev, int fd)
{
   struct udev_device *device;
   const char *id_path_tag_tmp;
   char *id_path_tag;
   UDEV_SYMBOL(const char *, udev_device_get_property_value,
               (struct udev_device *, const char *));
   UDEV_SYMBOL(struct udev_device *, udev_device_unref,
               (struct udev_device *));

   device = udev_device_new_from_fd(udev, fd);
   if (!device)
      return NULL;

   id_path_tag_tmp = udev_device_get_property_value(device, "ID_PATH_TAG");
   if (!id_path_tag_tmp)
      return NULL;

   id_path_tag = strdup(id_path_tag_tmp);

   udev_device_unref(device);
   return id_path_tag;
}

int
loader_open_device(const char *device_name)
{
   int fd;
#ifdef O_CLOEXEC
   fd = open(device_name, O_RDWR | O_CLOEXEC);
   if (fd == -1 && errno == EINVAL)
#endif
   {
      fd = open(device_name, O_RDWR);
      if (fd != -1)
         fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
   }
   return fd;
}

#ifdef USE_DRICONF
const char __driConfigOptionsLoader[] =
DRI_CONF_BEGIN
    DRI_CONF_SECTION_INITIALIZATION
        DRI_CONF_DEVICE_ID_PATH_TAG()
    DRI_CONF_SECTION_END
DRI_CONF_END;
#endif

int loader_get_user_preferred_fd(int default_fd, int *different_device)
{
   struct udev *udev;
#ifdef USE_DRICONF
   driOptionCache defaultInitOptions;
   driOptionCache userInitOptions;
#endif
   const char *dri_prime = getenv("DRI_PRIME");
   char *prime = NULL;
   int is_different_device = 0, fd = default_fd;
   char *default_device_id_path_tag;
   char *device_name = NULL;
   char another_tag = 0;
   UDEV_SYMBOL(struct udev *, udev_new, (void));
   UDEV_SYMBOL(struct udev *, udev_unref, (struct udev *));

   if (dri_prime)
      prime = strdup(dri_prime);
#ifdef USE_DRICONF
   else {
      driParseOptionInfo(&defaultInitOptions, __driConfigOptionsLoader);
      driParseConfigFiles(&userInitOptions, &defaultInitOptions, 0, "loader");
      if (driCheckOption(&userInitOptions, "device_id", DRI_STRING))
         prime = strdup(driQueryOptionstr(&userInitOptions, "device_id"));
      driDestroyOptionCache(&userInitOptions);
      driDestroyOptionInfo(&defaultInitOptions);
   }
#endif

   if (prime == NULL) {
      *different_device = 0;
      return default_fd;
   }

   udev = udev_new();
   if (!udev)
      goto prime_clean;

   default_device_id_path_tag = get_id_path_tag_from_fd(udev, default_fd);
   if (!default_device_id_path_tag)
      goto udev_clean;

   is_different_device = 1;
   /* two format are supported:
    * "1": choose any other card than the card used by default.
    * id_path_tag: (for example "pci-0000_02_00_0") choose the card
    * with this id_path_tag.
    */
   if (!strcmp(prime,"1")) {
      free(prime);
      prime = strdup(default_device_id_path_tag);
      /* request a card with a different card than the default card */
      another_tag = 1;
   } else if (!strcmp(default_device_id_path_tag, prime))
      /* we are to get a new fd (render-node) of the same device */
      is_different_device = 0;

   device_name = get_render_node_from_id_path_tag(udev,
                                                  prime,
                                                  another_tag);
   if (device_name == NULL) {
      is_different_device = 0;
      goto default_device_clean;
   }

   fd = loader_open_device(device_name);
   if (fd >= 0) {
      close(default_fd);
   } else {
      fd = default_fd;
      is_different_device = 0;
   }
   free(device_name);

 default_device_clean:
   free(default_device_id_path_tag);
 udev_clean:
   udev_unref(udev);
 prime_clean:
   free(prime);

   *different_device = is_different_device;
   return fd;
}
#else
int loader_get_user_preferred_fd(int default_fd, int *different_device)
{
   *different_device = 0;
   return default_fd;
}
#endif

#if defined(HAVE_SYSFS)
static int
dev_node_from_fd(int fd, unsigned int *maj, unsigned int *min)
{
   struct stat buf;

   if (fstat(fd, &buf) < 0) {
      log_(_LOADER_WARNING, "MESA-LOADER: failed to stat fd %d\n", fd);
      return -1;
   }

   if (!S_ISCHR(buf.st_mode)) {
      log_(_LOADER_WARNING, "MESA-LOADER: fd %d not a character device\n", fd);
      return -1;
   }

   *maj = major(buf.st_rdev);
   *min = minor(buf.st_rdev);

   return 0;
}

static int
sysfs_get_pci_id_for_fd(int fd, int *vendor_id, int *chip_id)
{
   unsigned int maj, min;
   FILE *f;
   char buf[0x40];

   if (dev_node_from_fd(fd, &maj, &min) < 0) {
      *chip_id = -1;
      return 0;
   }

   snprintf(buf, sizeof(buf), "/sys/dev/char/%d:%d/device/vendor", maj, min);
   if (!(f = fopen(buf, "r"))) {
      *chip_id = -1;
      return 0;
   }
   if (fscanf(f, "%x", vendor_id) != 1) {
      *chip_id = -1;
      fclose(f);
      return 0;
   }
   fclose(f);
   snprintf(buf, sizeof(buf), "/sys/dev/char/%d:%d/device/device", maj, min);
   if (!(f = fopen(buf, "r"))) {
      *chip_id = -1;
      return 0;
   }
   if (fscanf(f, "%x", chip_id) != 1) {
      *chip_id = -1;
      fclose(f);
      return 0;
   }
   fclose(f);
   return 1;
}
#endif

#if !defined(__NOT_HAVE_DRM_H)
/* for i915 */
#include <i915_drm.h>
/* for radeon */
#include <radeon_drm.h>

static int
drm_get_pci_id_for_fd(int fd, int *vendor_id, int *chip_id)
{
   drmVersionPtr version;

   *chip_id = -1;

   version = drmGetVersion(fd);
   if (!version) {
      log_(_LOADER_WARNING, "MESA-LOADER: invalid drm fd\n");
      return 0;
   }
   if (!version->name) {
      log_(_LOADER_WARNING, "MESA-LOADER: unable to determine the driver name\n");
      drmFreeVersion(version);
      return 0;
   }

   if (strcmp(version->name, "i915") == 0) {
      struct drm_i915_getparam gp;
      int ret;

      *vendor_id = 0x8086;

      memset(&gp, 0, sizeof(gp));
      gp.param = I915_PARAM_CHIPSET_ID;
      gp.value = chip_id;
      ret = drmCommandWriteRead(fd, DRM_I915_GETPARAM, &gp, sizeof(gp));
      if (ret) {
         log_(_LOADER_WARNING, "MESA-LOADER: failed to get param for i915\n");
	 *chip_id = -1;
      }
   }
   else if (strcmp(version->name, "radeon") == 0) {
      struct drm_radeon_info info;
      int ret;

      *vendor_id = 0x1002;

      memset(&info, 0, sizeof(info));
      info.request = RADEON_INFO_DEVICE_ID;
      info.value = (unsigned long) chip_id;
      ret = drmCommandWriteRead(fd, DRM_RADEON_INFO, &info, sizeof(info));
      if (ret) {
         log_(_LOADER_WARNING, "MESA-LOADER: failed to get info for radeon\n");
	 *chip_id = -1;
      }
   }
   else if (strcmp(version->name, "nouveau") == 0) {
      *vendor_id = 0x10de;
      /* not used */
      *chip_id = 0;
   }
   else if (strcmp(version->name, "vmwgfx") == 0) {
      *vendor_id = 0x15ad;
      /* assume SVGA II */
      *chip_id = 0x0405;
   }

   drmFreeVersion(version);

   return (*chip_id >= 0);
}
#endif


int
loader_get_pci_id_for_fd(int fd, int *vendor_id, int *chip_id)
{
#if HAVE_LIBUDEV
   if (libudev_get_pci_id_for_fd(fd, vendor_id, chip_id))
      return 1;
#endif
#if HAVE_SYSFS
   if (sysfs_get_pci_id_for_fd(fd, vendor_id, chip_id))
      return 1;
#endif
#if !defined(__NOT_HAVE_DRM_H)
   if (drm_get_pci_id_for_fd(fd, vendor_id, chip_id))
      return 1;
#endif
   return 0;
}


#ifdef HAVE_LIBUDEV
static char *
libudev_get_device_name_for_fd(int fd)
{
   char *device_name = NULL;
   struct udev *udev;
   struct udev_device *device;
   const char *const_device_name;
   UDEV_SYMBOL(struct udev *, udev_new, (void));
   UDEV_SYMBOL(const char *, udev_device_get_devnode,
               (struct udev_device *));
   UDEV_SYMBOL(struct udev_device *, udev_device_unref,
               (struct udev_device *));
   UDEV_SYMBOL(struct udev *, udev_unref, (struct udev *));

   if (dlsym_failed)
      return NULL;

   udev = udev_new();
   device = udev_device_new_from_fd(udev, fd);
   if (device == NULL)
      return NULL;

   const_device_name = udev_device_get_devnode(device);
   if (!const_device_name)
      goto out;
   device_name = strdup(const_device_name);

out:
   udev_device_unref(device);
   udev_unref(udev);
   return device_name;
}
#endif


#if HAVE_SYSFS
static char *
sysfs_get_device_name_for_fd(int fd)
{
   char *device_name = NULL;
   unsigned int maj, min;
   FILE *f;
   char buf[0x40];
   static const char match[9] = "\0DEVNAME=";
   int expected = 1;

   if (dev_node_from_fd(fd, &maj, &min) < 0)
      return NULL;

   snprintf(buf, sizeof(buf), "/sys/dev/char/%d:%d/uevent", maj, min);
   if (!(f = fopen(buf, "r")))
       return NULL;

   while (expected < sizeof(match)) {
      int c = getc(f);

      if (c == EOF) {
         fclose(f);
         return NULL;
      } else if (c == match[expected] )
         expected++;
      else
         expected = 0;
   }

   strcpy(buf, "/dev/");
   if (fgets(buf + 5, sizeof(buf) - 5, f))
      device_name = strdup(buf);

   fclose(f);
   return device_name;
}
#endif


char *
loader_get_device_name_for_fd(int fd)
{
   char *result = NULL;

#if HAVE_LIBUDEV
   if ((result = libudev_get_device_name_for_fd(fd)))
      return result;
#endif
#if HAVE_SYSFS
   if ((result = sysfs_get_device_name_for_fd(fd)))
      return result;
#endif
   return result;
}

char *
loader_get_driver_for_fd(int fd, unsigned driver_types)
{
   int vendor_id, chip_id, i, j;
   char *driver = NULL;

   if (!driver_types)
      driver_types = _LOADER_GALLIUM | _LOADER_DRI;

   if (!loader_get_pci_id_for_fd(fd, &vendor_id, &chip_id)) {

#ifndef __NOT_HAVE_DRM_H
      /* fallback to drmGetVersion(): */
      drmVersionPtr version = drmGetVersion(fd);

      if (!version) {
         log_(_LOADER_WARNING, "failed to get driver name for fd %d\n", fd);
         return NULL;
      }

      driver = strndup(version->name, version->name_len);
      log_(_LOADER_INFO, "using driver %s for %d\n", driver, fd);

      drmFreeVersion(version);
#endif

      return driver;
   }

   for (i = 0; driver_map[i].driver; i++) {
      if (vendor_id != driver_map[i].vendor_id)
         continue;

      if (!(driver_types & driver_map[i].driver_types))
         continue;

      if (driver_map[i].predicate && !driver_map[i].predicate(fd))
         continue;

      if (driver_map[i].num_chips_ids == -1) {
         driver = strdup(driver_map[i].driver);
         goto out;
      }

      for (j = 0; j < driver_map[i].num_chips_ids; j++)
         if (driver_map[i].chip_ids[j] == chip_id) {
            driver = strdup(driver_map[i].driver);
            goto out;
         }
   }

out:
   log_(driver ? _LOADER_DEBUG : _LOADER_WARNING,
         "pci id for fd %d: %04x:%04x, driver %s\n",
         fd, vendor_id, chip_id, driver);
   return driver;
}

void
loader_set_logger(void (*logger)(int level, const char *fmt, ...))
{
   log_ = logger;
}