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 * assinged 11 * 12 * After PCI devices are glued with ACPI devices 13 * acpi_get_physical_pci_device() 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 (or display output) 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 and display output 28 * switching. 29 * 30 * If CONFIG_ACPI_VIDEO is neither set as "compiled in" (y) nor as a module (m) 31 * this file will not be compiled, acpi_video_get_capabilities() and 32 * acpi_video_backlight_support() will always return 0 and vendor specific 33 * drivers always can handle backlight. 34 * 35 */ 36 37 #include <linux/acpi.h> 38 #include <linux/dmi.h> 39 40 ACPI_MODULE_NAME("video"); 41 #define _COMPONENT ACPI_VIDEO_COMPONENT 42 43 static long acpi_video_support; 44 static bool acpi_video_caps_checked; 45 46 static acpi_status 47 acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context, 48 void **retyurn_value) 49 { 50 long *cap = context; 51 acpi_handle h_dummy; 52 53 if (ACPI_SUCCESS(acpi_get_handle(handle, "_BCM", &h_dummy)) && 54 ACPI_SUCCESS(acpi_get_handle(handle, "_BCL", &h_dummy))) { 55 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight " 56 "support\n")); 57 *cap |= ACPI_VIDEO_BACKLIGHT; 58 /* We have backlight support, no need to scan further */ 59 return AE_CTRL_TERMINATE; 60 } 61 return 0; 62 } 63 64 /* Returns true if the device is a video device which can be handled by 65 * video.ko. 66 * The device will get a Linux specific CID added in scan.c to 67 * identify the device as an ACPI graphics device 68 * Be aware that the graphics device may not be physically present 69 * Use acpi_video_get_capabilities() to detect general ACPI video 70 * capabilities of present cards 71 */ 72 long acpi_is_video_device(struct acpi_device *device) 73 { 74 acpi_handle h_dummy; 75 long video_caps = 0; 76 77 if (!device) 78 return 0; 79 80 /* Does this device able to support video switching ? */ 81 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) && 82 ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOS", &h_dummy))) 83 video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING; 84 85 /* Does this device able to retrieve a video ROM ? */ 86 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy))) 87 video_caps |= ACPI_VIDEO_ROM_AVAILABLE; 88 89 /* Does this device able to configure which video head to be POSTed ? */ 90 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_VPO", &h_dummy)) && 91 ACPI_SUCCESS(acpi_get_handle(device->handle, "_GPD", &h_dummy)) && 92 ACPI_SUCCESS(acpi_get_handle(device->handle, "_SPD", &h_dummy))) 93 video_caps |= ACPI_VIDEO_DEVICE_POSTING; 94 95 /* Only check for backlight functionality if one of the above hit. */ 96 if (video_caps) 97 acpi_walk_namespace(ACPI_TYPE_DEVICE, device->handle, 98 ACPI_UINT32_MAX, acpi_backlight_cap_match, 99 &video_caps, NULL); 100 101 return video_caps; 102 } 103 EXPORT_SYMBOL(acpi_is_video_device); 104 105 static acpi_status 106 find_video(acpi_handle handle, u32 lvl, void *context, void **rv) 107 { 108 long *cap = context; 109 struct device *dev; 110 struct acpi_device *acpi_dev; 111 112 const struct acpi_device_id video_ids[] = { 113 {ACPI_VIDEO_HID, 0}, 114 {"", 0}, 115 }; 116 if (acpi_bus_get_device(handle, &acpi_dev)) 117 return AE_OK; 118 119 if (!acpi_match_device_ids(acpi_dev, video_ids)) { 120 dev = acpi_get_physical_pci_device(handle); 121 if (!dev) 122 return AE_OK; 123 put_device(dev); 124 *cap |= acpi_is_video_device(acpi_dev); 125 } 126 return AE_OK; 127 } 128 129 /* 130 * Returns the video capabilities of a specific ACPI graphics device 131 * 132 * if NULL is passed as argument all ACPI devices are enumerated and 133 * all graphics capabilities of physically present devices are 134 * summerized and returned. This is cached and done only once. 135 */ 136 long acpi_video_get_capabilities(acpi_handle graphics_handle) 137 { 138 long caps = 0; 139 struct acpi_device *tmp_dev; 140 acpi_status status; 141 142 if (acpi_video_caps_checked && graphics_handle == NULL) 143 return acpi_video_support; 144 145 if (!graphics_handle) { 146 /* Only do the global walk through all graphics devices once */ 147 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 148 ACPI_UINT32_MAX, find_video, 149 &caps, NULL); 150 /* There might be boot param flags set already... */ 151 acpi_video_support |= caps; 152 acpi_video_caps_checked = 1; 153 /* Add blacklists here. Be careful to use the right *DMI* bits 154 * to still be able to override logic via boot params, e.g.: 155 * 156 * if (dmi_name_in_vendors("XY")) { 157 * acpi_video_support |= 158 * ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR; 159 * acpi_video_support |= 160 * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 161 *} 162 */ 163 } else { 164 status = acpi_bus_get_device(graphics_handle, &tmp_dev); 165 if (ACPI_FAILURE(status)) { 166 ACPI_EXCEPTION((AE_INFO, status, "Invalid device")); 167 return 0; 168 } 169 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle, 170 ACPI_UINT32_MAX, find_video, 171 &caps, NULL); 172 } 173 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n", 174 graphics_handle ? caps : acpi_video_support, 175 graphics_handle ? "on device " : "in general", 176 graphics_handle ? acpi_device_bid(tmp_dev) : "")); 177 return caps; 178 } 179 EXPORT_SYMBOL(acpi_video_get_capabilities); 180 181 /* Returns true if video.ko can do backlight switching */ 182 int acpi_video_backlight_support(void) 183 { 184 /* 185 * We must check whether the ACPI graphics device is physically plugged 186 * in. Therefore this must be called after binding PCI and ACPI devices 187 */ 188 if (!acpi_video_caps_checked) 189 acpi_video_get_capabilities(NULL); 190 191 /* First check for boot param -> highest prio */ 192 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR) 193 return 0; 194 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO) 195 return 1; 196 197 /* Then check for DMI blacklist -> second highest prio */ 198 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR) 199 return 0; 200 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO) 201 return 1; 202 203 /* Then go the default way */ 204 return acpi_video_support & ACPI_VIDEO_BACKLIGHT; 205 } 206 EXPORT_SYMBOL(acpi_video_backlight_support); 207 208 /* 209 * Returns true if video.ko can do display output switching. 210 * This does not work well/at all with binary graphics drivers 211 * which disable system io ranges and do it on their own. 212 */ 213 int acpi_video_display_switch_support(void) 214 { 215 if (!acpi_video_caps_checked) 216 acpi_video_get_capabilities(NULL); 217 218 if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR) 219 return 0; 220 else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO) 221 return 1; 222 223 if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR) 224 return 0; 225 else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO) 226 return 1; 227 228 return acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING; 229 } 230 EXPORT_SYMBOL(acpi_video_display_switch_support); 231 232 /* 233 * Use acpi_display_output=vendor/video or acpi_backlight=vendor/video 234 * To force that backlight or display output switching is processed by vendor 235 * specific acpi drivers or video.ko driver. 236 */ 237 static int __init acpi_backlight(char *str) 238 { 239 if (str == NULL || *str == '\0') 240 return 1; 241 else { 242 if (!strcmp("vendor", str)) 243 acpi_video_support |= 244 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR; 245 if (!strcmp("video", str)) 246 acpi_video_support |= 247 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO; 248 } 249 return 1; 250 } 251 __setup("acpi_backlight=", acpi_backlight); 252 253 static int __init acpi_display_output(char *str) 254 { 255 if (str == NULL || *str == '\0') 256 return 1; 257 else { 258 if (!strcmp("vendor", str)) 259 acpi_video_support |= 260 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR; 261 if (!strcmp("video", str)) 262 acpi_video_support |= 263 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO; 264 } 265 return 1; 266 } 267 __setup("acpi_display_output=", acpi_display_output); 268