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1 | /* |
2 | * Copyright (C) 2008 SuSE Linux Products GmbH |
3 | * Thomas Renninger <trenn@suse.de> |
4 | * |
5 | * May be copied or modified under the terms of the GNU General Public License |
6 | * |
7 | * video_detect.c: |
8 | * Provides acpi_is_video_device() for early scanning of ACPI devices in scan.c |
9 | * There a Linux specific (Spec does not provide a HID for video devices) is |
10 | * assigned |
11 | * |
12 | * After PCI devices are glued with ACPI devices |
13 | * acpi_get_pci_dev() can be called to identify ACPI graphics |
14 | * devices for which a real graphics card is plugged in |
15 | * |
16 | * Now acpi_video_get_capabilities() can be called to check which |
17 | * capabilities the graphics cards plugged in support. The check for general |
18 | * video capabilities will be triggered by the first caller of |
19 | * acpi_video_get_capabilities(NULL); which will happen when the first |
20 | * backlight switching supporting driver calls: |
21 | * acpi_video_backlight_support(); |
22 | * |
23 | * Depending on whether ACPI graphics extensions (cmp. ACPI spec Appendix B) |
24 | * are available, video.ko should be used to handle the device. |
25 | * |
26 | * Otherwise vendor specific drivers like thinkpad_acpi, asus_acpi, |
27 | * sony_acpi,... can take care about backlight brightness. |
28 | * |
29 | * If CONFIG_ACPI_VIDEO is neither set as "compiled in" (y) nor as a module (m) |
30 | * this file will not be compiled, acpi_video_get_capabilities() and |
31 | * acpi_video_backlight_support() will always return 0 and vendor specific |
32 | * drivers always can handle backlight. |
33 | * |
34 | */ |
35 | |
36 | #include <linux/acpi.h> |
37 | #include <linux/dmi.h> |
38 | #include <linux/pci.h> |
39 | |
40 | #define PREFIX "ACPI: " |
41 | |
42 | ACPI_MODULE_NAME("video"); |
43 | #define _COMPONENT ACPI_VIDEO_COMPONENT |
44 | |
45 | static long acpi_video_support; |
46 | static bool acpi_video_caps_checked; |
47 | |
48 | static acpi_status |
49 | acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context, |
50 | void **retyurn_value) |
51 | { |
52 | long *cap = context; |
53 | acpi_handle h_dummy; |
54 | |
55 | if (ACPI_SUCCESS(acpi_get_handle(handle, "_BCM", &h_dummy)) && |
56 | ACPI_SUCCESS(acpi_get_handle(handle, "_BCL", &h_dummy))) { |
57 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight " |
58 | "support\n")); |
59 | *cap |= ACPI_VIDEO_BACKLIGHT; |
60 | if (ACPI_FAILURE(acpi_get_handle(handle, "_BQC", &h_dummy))) |
61 | printk(KERN_WARNING FW_BUG PREFIX "No _BQC method, " |
62 | "cannot determine initial brightness\n"); |
63 | /* We have backlight support, no need to scan further */ |
64 | return AE_CTRL_TERMINATE; |
65 | } |
66 | return 0; |
67 | } |
68 | |
69 | /* Returns true if the device is a video device which can be handled by |
70 | * video.ko. |
71 | * The device will get a Linux specific CID added in scan.c to |
72 | * identify the device as an ACPI graphics device |
73 | * Be aware that the graphics device may not be physically present |
74 | * Use acpi_video_get_capabilities() to detect general ACPI video |
75 | * capabilities of present cards |
76 | */ |
77 | long acpi_is_video_device(struct acpi_device *device) |
78 | { |
79 | acpi_handle h_dummy; |
80 | long video_caps = 0; |
81 | |
82 | if (!device) |
83 | return 0; |
84 | |
85 | /* Is this device able to support video switching ? */ |
86 | if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) || |
87 | ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOS", &h_dummy))) |
88 | video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING; |
89 | |
90 | /* Is this device able to retrieve a video ROM ? */ |
91 | if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy))) |
92 | video_caps |= ACPI_VIDEO_ROM_AVAILABLE; |
93 | |
94 | /* Is this device able to configure which video head to be POSTed ? */ |
95 | if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_VPO", &h_dummy)) && |
96 | ACPI_SUCCESS(acpi_get_handle(device->handle, "_GPD", &h_dummy)) && |
97 | ACPI_SUCCESS(acpi_get_handle(device->handle, "_SPD", &h_dummy))) |
98 | video_caps |= ACPI_VIDEO_DEVICE_POSTING; |
99 | |
100 | /* Only check for backlight functionality if one of the above hit. */ |
101 | if (video_caps) |
102 | acpi_walk_namespace(ACPI_TYPE_DEVICE, device->handle, |
103 | ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL, |
104 | &video_caps, NULL); |
105 | |
106 | return video_caps; |
107 | } |
108 | EXPORT_SYMBOL(acpi_is_video_device); |
109 | |
110 | static acpi_status |
111 | find_video(acpi_handle handle, u32 lvl, void *context, void **rv) |
112 | { |
113 | long *cap = context; |
114 | struct pci_dev *dev; |
115 | struct acpi_device *acpi_dev; |
116 | |
117 | const struct acpi_device_id video_ids[] = { |
118 | {ACPI_VIDEO_HID, 0}, |
119 | {"", 0}, |
120 | }; |
121 | if (acpi_bus_get_device(handle, &acpi_dev)) |
122 | return AE_OK; |
123 | |
124 | if (!acpi_match_device_ids(acpi_dev, video_ids)) { |
125 | dev = acpi_get_pci_dev(handle); |
126 | if (!dev) |
127 | return AE_OK; |
128 | pci_dev_put(dev); |
129 | *cap |= acpi_is_video_device(acpi_dev); |
130 | } |
131 | return AE_OK; |
132 | } |
133 | |
134 | /* |
135 | * Returns the video capabilities of a specific ACPI graphics device |
136 | * |
137 | * if NULL is passed as argument all ACPI devices are enumerated and |
138 | * all graphics capabilities of physically present devices are |
139 | * summarized and returned. This is cached and done only once. |
140 | */ |
141 | long acpi_video_get_capabilities(acpi_handle graphics_handle) |
142 | { |
143 | long caps = 0; |
144 | struct acpi_device *tmp_dev; |
145 | acpi_status status; |
146 | |
147 | if (acpi_video_caps_checked && graphics_handle == NULL) |
148 | return acpi_video_support; |
149 | |
150 | if (!graphics_handle) { |
151 | /* Only do the global walk through all graphics devices once */ |
152 | acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, |
153 | ACPI_UINT32_MAX, find_video, NULL, |
154 | &caps, NULL); |
155 | /* There might be boot param flags set already... */ |
156 | acpi_video_support |= caps; |
157 | acpi_video_caps_checked = 1; |
158 | /* Add blacklists here. Be careful to use the right *DMI* bits |
159 | * to still be able to override logic via boot params, e.g.: |
160 | * |
161 | * if (dmi_name_in_vendors("XY")) { |
162 | * acpi_video_support |= |
163 | * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; |
164 | *} |
165 | */ |
166 | } else { |
167 | status = acpi_bus_get_device(graphics_handle, &tmp_dev); |
168 | if (ACPI_FAILURE(status)) { |
169 | ACPI_EXCEPTION((AE_INFO, status, "Invalid device")); |
170 | return 0; |
171 | } |
172 | acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle, |
173 | ACPI_UINT32_MAX, find_video, NULL, |
174 | &caps, NULL); |
175 | } |
176 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n", |
177 | graphics_handle ? caps : acpi_video_support, |
178 | graphics_handle ? "on device " : "in general", |
179 | graphics_handle ? acpi_device_bid(tmp_dev) : "")); |
180 | return caps; |
181 | } |
182 | EXPORT_SYMBOL(acpi_video_get_capabilities); |
183 | |
184 | /* Returns true if video.ko can do backlight switching */ |
185 | int acpi_video_backlight_support(void) |
186 | { |
187 | /* |
188 | * We must check whether the ACPI graphics device is physically plugged |
189 | * in. Therefore this must be called after binding PCI and ACPI devices |
190 | */ |
191 | if (!acpi_video_caps_checked) |
192 | acpi_video_get_capabilities(NULL); |
193 | |
194 | /* First check for boot param -> highest prio */ |
195 | if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR) |
196 | return 0; |
197 | else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO) |
198 | return 1; |
199 | |
200 | /* Then check for DMI blacklist -> second highest prio */ |
201 | if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR) |
202 | return 0; |
203 | else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO) |
204 | return 1; |
205 | |
206 | /* Then go the default way */ |
207 | return acpi_video_support & ACPI_VIDEO_BACKLIGHT; |
208 | } |
209 | EXPORT_SYMBOL(acpi_video_backlight_support); |
210 | |
211 | /* |
212 | * Use acpi_backlight=vendor/video to force that backlight switching |
213 | * is processed by vendor specific acpi drivers or video.ko driver. |
214 | */ |
215 | static int __init acpi_backlight(char *str) |
216 | { |
217 | if (str == NULL || *str == '\0') |
218 | return 1; |
219 | else { |
220 | if (!strcmp("vendor", str)) |
221 | acpi_video_support |= |
222 | ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR; |
223 | if (!strcmp("video", str)) |
224 | acpi_video_support |= |
225 | ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO; |
226 | } |
227 | return 1; |
228 | } |
229 | __setup("acpi_backlight=", acpi_backlight); |
230 |
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