Root/drivers/acpi/video_detect.c

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-laptop,
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/export.h>
37#include <linux/acpi.h>
38#include <linux/dmi.h>
39#include <linux/pci.h>
40
41#define PREFIX "ACPI: "
42
43ACPI_MODULE_NAME("video");
44#define _COMPONENT ACPI_VIDEO_COMPONENT
45
46static long acpi_video_support;
47static bool acpi_video_caps_checked;
48
49static acpi_status
50acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
51              void **retyurn_value)
52{
53    long *cap = context;
54    acpi_handle h_dummy;
55
56    if (ACPI_SUCCESS(acpi_get_handle(handle, "_BCM", &h_dummy)) &&
57        ACPI_SUCCESS(acpi_get_handle(handle, "_BCL", &h_dummy))) {
58        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight "
59                  "support\n"));
60        *cap |= ACPI_VIDEO_BACKLIGHT;
61        if (ACPI_FAILURE(acpi_get_handle(handle, "_BQC", &h_dummy)))
62            printk(KERN_WARNING FW_BUG PREFIX "No _BQC method, "
63                "cannot determine initial brightness\n");
64        /* We have backlight support, no need to scan further */
65        return AE_CTRL_TERMINATE;
66    }
67    return 0;
68}
69
70/* Returns true if the device is a video device which can be handled by
71 * video.ko.
72 * The device will get a Linux specific CID added in scan.c to
73 * identify the device as an ACPI graphics device
74 * Be aware that the graphics device may not be physically present
75 * Use acpi_video_get_capabilities() to detect general ACPI video
76 * capabilities of present cards
77 */
78long acpi_is_video_device(struct acpi_device *device)
79{
80    acpi_handle h_dummy;
81    long video_caps = 0;
82
83    if (!device)
84        return 0;
85
86    /* Is this device able to support video switching ? */
87    if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) ||
88        ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOS", &h_dummy)))
89        video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
90
91    /* Is this device able to retrieve a video ROM ? */
92    if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy)))
93        video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
94
95    /* Is this device able to configure which video head to be POSTed ? */
96    if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_VPO", &h_dummy)) &&
97        ACPI_SUCCESS(acpi_get_handle(device->handle, "_GPD", &h_dummy)) &&
98        ACPI_SUCCESS(acpi_get_handle(device->handle, "_SPD", &h_dummy)))
99        video_caps |= ACPI_VIDEO_DEVICE_POSTING;
100
101    /* Only check for backlight functionality if one of the above hit. */
102    if (video_caps)
103        acpi_walk_namespace(ACPI_TYPE_DEVICE, device->handle,
104                    ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL,
105                    &video_caps, NULL);
106
107    return video_caps;
108}
109EXPORT_SYMBOL(acpi_is_video_device);
110
111static acpi_status
112find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
113{
114    long *cap = context;
115    struct pci_dev *dev;
116    struct acpi_device *acpi_dev;
117
118    const struct acpi_device_id video_ids[] = {
119        {ACPI_VIDEO_HID, 0},
120        {"", 0},
121    };
122    if (acpi_bus_get_device(handle, &acpi_dev))
123        return AE_OK;
124
125    if (!acpi_match_device_ids(acpi_dev, video_ids)) {
126        dev = acpi_get_pci_dev(handle);
127        if (!dev)
128            return AE_OK;
129        pci_dev_put(dev);
130        *cap |= acpi_is_video_device(acpi_dev);
131    }
132    return AE_OK;
133}
134
135/* Force to use vendor driver when the ACPI device is known to be
136 * buggy */
137static int video_detect_force_vendor(const struct dmi_system_id *d)
138{
139    acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
140    return 0;
141}
142
143static struct dmi_system_id video_detect_dmi_table[] = {
144    /* On Samsung X360, the BIOS will set a flag (VDRV) if generic
145     * ACPI backlight device is used. This flag will definitively break
146     * the backlight interface (even the vendor interface) untill next
147     * reboot. It's why we should prevent video.ko from being used here
148     * and we can't rely on a later call to acpi_video_unregister().
149     */
150    {
151     .callback = video_detect_force_vendor,
152     .ident = "X360",
153     .matches = {
154        DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
155        DMI_MATCH(DMI_PRODUCT_NAME, "X360"),
156        DMI_MATCH(DMI_BOARD_NAME, "X360"),
157        },
158    },
159    { },
160};
161
162/*
163 * Returns the video capabilities of a specific ACPI graphics device
164 *
165 * if NULL is passed as argument all ACPI devices are enumerated and
166 * all graphics capabilities of physically present devices are
167 * summarized and returned. This is cached and done only once.
168 */
169long acpi_video_get_capabilities(acpi_handle graphics_handle)
170{
171    long caps = 0;
172    struct acpi_device *tmp_dev;
173    acpi_status status;
174
175    if (acpi_video_caps_checked && graphics_handle == NULL)
176        return acpi_video_support;
177
178    if (!graphics_handle) {
179        /* Only do the global walk through all graphics devices once */
180        acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
181                    ACPI_UINT32_MAX, find_video, NULL,
182                    &caps, NULL);
183        /* There might be boot param flags set already... */
184        acpi_video_support |= caps;
185        acpi_video_caps_checked = 1;
186        /* Add blacklists here. Be careful to use the right *DMI* bits
187         * to still be able to override logic via boot params, e.g.:
188         *
189         * if (dmi_name_in_vendors("XY")) {
190         * acpi_video_support |=
191         * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
192         *}
193         */
194
195        dmi_check_system(video_detect_dmi_table);
196    } else {
197        status = acpi_bus_get_device(graphics_handle, &tmp_dev);
198        if (ACPI_FAILURE(status)) {
199            ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
200            return 0;
201        }
202        acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
203                    ACPI_UINT32_MAX, find_video, NULL,
204                    &caps, NULL);
205    }
206    ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
207              graphics_handle ? caps : acpi_video_support,
208              graphics_handle ? "on device " : "in general",
209              graphics_handle ? acpi_device_bid(tmp_dev) : ""));
210    return caps;
211}
212EXPORT_SYMBOL(acpi_video_get_capabilities);
213
214static void acpi_video_caps_check(void)
215{
216    /*
217     * We must check whether the ACPI graphics device is physically plugged
218     * in. Therefore this must be called after binding PCI and ACPI devices
219     */
220    if (!acpi_video_caps_checked)
221        acpi_video_get_capabilities(NULL);
222}
223
224/* Promote the vendor interface instead of the generic video module.
225 * This function allow DMI blacklists to be implemented by externals
226 * platform drivers instead of putting a big blacklist in video_detect.c
227 * After calling this function you will probably want to call
228 * acpi_video_unregister() to make sure the video module is not loaded
229 */
230void acpi_video_dmi_promote_vendor(void)
231{
232    acpi_video_caps_check();
233    acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
234}
235EXPORT_SYMBOL(acpi_video_dmi_promote_vendor);
236
237/* To be called when a driver who previously promoted the vendor
238 * interface */
239void acpi_video_dmi_demote_vendor(void)
240{
241    acpi_video_caps_check();
242    acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
243}
244EXPORT_SYMBOL(acpi_video_dmi_demote_vendor);
245
246/* Returns true if video.ko can do backlight switching */
247int acpi_video_backlight_support(void)
248{
249    acpi_video_caps_check();
250
251    /* First check for boot param -> highest prio */
252    if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
253        return 0;
254    else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
255        return 1;
256
257    /* Then check for DMI blacklist -> second highest prio */
258    if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
259        return 0;
260    else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
261        return 1;
262
263    /* Then go the default way */
264    return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
265}
266EXPORT_SYMBOL(acpi_video_backlight_support);
267
268/*
269 * Use acpi_backlight=vendor/video to force that backlight switching
270 * is processed by vendor specific acpi drivers or video.ko driver.
271 */
272static int __init acpi_backlight(char *str)
273{
274    if (str == NULL || *str == '\0')
275        return 1;
276    else {
277        if (!strcmp("vendor", str))
278            acpi_video_support |=
279                ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
280        if (!strcmp("video", str))
281            acpi_video_support |=
282                ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
283    }
284    return 1;
285}
286__setup("acpi_backlight=", acpi_backlight);
287

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