1 /*-
2 * Copyright (c) 2022 Beckhoff Automation GmbH & Co. KG
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 *
25 */
26
27 #include <sys/param.h>
28 #include <sys/systm.h>
29
30 #include <video/cmdline.h>
31
32 const char *
video_get_options(const char * connector_name)33 video_get_options(const char *connector_name)
34 {
35 char tunable[64];
36 const char *options;
37
38 /*
39 * A user may use loader tunables to set a specific mode for the
40 * console. Tunables are read in the following order:
41 * 1. kern.vt.fb.modes.$connector_name
42 * 2. kern.vt.fb.default_mode
43 *
44 * Example of a mode specific to the LVDS connector:
45 * kern.vt.fb.modes.LVDS="1024x768"
46 *
47 * Example of a mode applied to all connectors not having a
48 * connector-specific mode:
49 * kern.vt.fb.default_mode="640x480"
50 */
51 snprintf(tunable, sizeof(tunable), "kern.vt.fb.modes.%s",
52 connector_name);
53 if (bootverbose) {
54 printf("[drm] Connector %s: get mode from tunables:\n", connector_name);
55 printf("[drm] - %s\n", tunable);
56 printf("[drm] - kern.vt.fb.default_mode\n");
57 }
58 options = kern_getenv(tunable);
59 if (options == NULL)
60 options = kern_getenv("kern.vt.fb.default_mode");
61
62 return (options);
63 }
64