1// SPDX-License-Identifier: MIT
2/*
3 * Copyright (C) 2020 Red Hat, Inc.
4 *
5 * Authors:
6 * Hans de Goede <hdegoede@redhat.com>
7 */
8
9#include <linux/acpi.h>
10#include <drm/drm_privacy_screen_machine.h>
11
12#ifdef CONFIG_X86
13static struct drm_privacy_screen_lookup arch_lookup;
14
15struct arch_init_data {
16 struct drm_privacy_screen_lookup lookup;
17 bool (*detect)(void);
18};
19
20#if IS_ENABLED(CONFIG_THINKPAD_ACPI)
21static acpi_status __init acpi_set_handle(acpi_handle handle, u32 level,
22 void *context, void **return_value)
23{
24 *(acpi_handle *)return_value = handle;
25 return AE_CTRL_TERMINATE;
26}
27
28static bool __init detect_thinkpad_privacy_screen(void)
29{
30 union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
31 struct acpi_object_list args = { .count = 1, .pointer = &obj, };
32 acpi_handle ec_handle = NULL;
33 unsigned long long output;
34 acpi_status status;
35
36 if (acpi_disabled)
37 return false;
38
39 /* Get embedded-controller handle */
40 status = acpi_get_devices(HID: "PNP0C09", user_function: acpi_set_handle, NULL, return_value: &ec_handle);
41 if (ACPI_FAILURE(status) || !ec_handle)
42 return false;
43
44 /* And call the privacy-screen get-status method */
45 status = acpi_evaluate_integer(handle: ec_handle, pathname: "HKEY.GSSS", arguments: &args, data: &output);
46 if (ACPI_FAILURE(status))
47 return false;
48
49 return (output & 0x10000) ? true : false;
50}
51#endif
52
53#if IS_ENABLED(CONFIG_CHROMEOS_PRIVACY_SCREEN)
54static bool __init detect_chromeos_privacy_screen(void)
55{
56 return acpi_dev_present(hid: "GOOG0010", NULL, hrv: -1);
57}
58#endif
59
60static const struct arch_init_data arch_init_data[] __initconst = {
61#if IS_ENABLED(CONFIG_THINKPAD_ACPI)
62 {
63 .lookup = {
64 .dev_id = NULL,
65 .con_id = NULL,
66 .provider = "privacy_screen-thinkpad_acpi",
67 },
68 .detect = detect_thinkpad_privacy_screen,
69 },
70#endif
71#if IS_ENABLED(CONFIG_CHROMEOS_PRIVACY_SCREEN)
72 {
73 .lookup = {
74 .dev_id = NULL,
75 .con_id = NULL,
76 .provider = "privacy_screen-GOOG0010:00",
77 },
78 .detect = detect_chromeos_privacy_screen,
79 },
80#endif
81};
82
83void __init drm_privacy_screen_lookup_init(void)
84{
85 int i;
86
87 for (i = 0; i < ARRAY_SIZE(arch_init_data); i++) {
88 if (!arch_init_data[i].detect())
89 continue;
90
91 pr_info("Found '%s' privacy-screen provider\n",
92 arch_init_data[i].lookup.provider);
93
94 /* Make a copy because arch_init_data is __initconst */
95 arch_lookup = arch_init_data[i].lookup;
96 drm_privacy_screen_lookup_add(lookup: &arch_lookup);
97 break;
98 }
99}
100
101void drm_privacy_screen_lookup_exit(void)
102{
103 if (arch_lookup.provider)
104 drm_privacy_screen_lookup_remove(lookup: &arch_lookup);
105}
106#endif /* ifdef CONFIG_X86 */
107

source code of linux/drivers/gpu/drm/drm_privacy_screen_x86.c