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_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 (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 #include <linux/pci.h> 40 41 #define PREFIX "ACPI: " 42 43 ACPI_MODULE_NAME("video"); 44 #define _COMPONENT ACPI_VIDEO_COMPONENT 45 46 static long acpi_video_support; 47 static bool acpi_video_caps_checked; 48 49 static acpi_status 50 acpi_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 "ACPI brightness " 63 "control misses _BQC function\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 */ 78 long 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 /* Does 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 /* Does 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 /* Does 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, 105 &video_caps, NULL); 106 107 return video_caps; 108 } 109 EXPORT_SYMBOL(acpi_is_video_device); 110 111 static acpi_status 112 find_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 /* 136 * Returns the video capabilities of a specific ACPI graphics device 137 * 138 * if NULL is passed as argument all ACPI devices are enumerated and 139 * all graphics capabilities of physically present devices are 140 * summerized and returned. This is cached and done only once. 141 */ 142 long acpi_video_get_capabilities(acpi_handle graphics_handle) 143 { 144 long caps = 0; 145 struct acpi_device *tmp_dev; 146 acpi_status status; 147 148 if (acpi_video_caps_checked && graphics_handle == NULL) 149 return acpi_video_support; 150 151 if (!graphics_handle) { 152 /* Only do the global walk through all graphics devices once */ 153 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 154 ACPI_UINT32_MAX, find_video, 155 &caps, NULL); 156 /* There might be boot param flags set already... */ 157 acpi_video_support |= caps; 158 acpi_video_caps_checked = 1; 159 /* Add blacklists here. Be careful to use the right *DMI* bits 160 * to still be able to override logic via boot params, e.g.: 161 * 162 * if (dmi_name_in_vendors("XY")) { 163 * acpi_video_support |= 164 * ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR; 165 * acpi_video_support |= 166 * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 167 *} 168 */ 169 } else { 170 status = acpi_bus_get_device(graphics_handle, &tmp_dev); 171 if (ACPI_FAILURE(status)) { 172 ACPI_EXCEPTION((AE_INFO, status, "Invalid device")); 173 return 0; 174 } 175 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle, 176 ACPI_UINT32_MAX, find_video, 177 &caps, NULL); 178 } 179 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n", 180 graphics_handle ? caps : acpi_video_support, 181 graphics_handle ? "on device " : "in general", 182 graphics_handle ? acpi_device_bid(tmp_dev) : "")); 183 return caps; 184 } 185 EXPORT_SYMBOL(acpi_video_get_capabilities); 186 187 /* Returns true if video.ko can do backlight switching */ 188 int acpi_video_backlight_support(void) 189 { 190 /* 191 * We must check whether the ACPI graphics device is physically plugged 192 * in. Therefore this must be called after binding PCI and ACPI devices 193 */ 194 if (!acpi_video_caps_checked) 195 acpi_video_get_capabilities(NULL); 196 197 /* First check for boot param -> highest prio */ 198 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR) 199 return 0; 200 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO) 201 return 1; 202 203 /* Then check for DMI blacklist -> second highest prio */ 204 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR) 205 return 0; 206 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO) 207 return 1; 208 209 /* Then go the default way */ 210 return acpi_video_support & ACPI_VIDEO_BACKLIGHT; 211 } 212 EXPORT_SYMBOL(acpi_video_backlight_support); 213 214 /* 215 * Returns true if video.ko can do display output switching. 216 * This does not work well/at all with binary graphics drivers 217 * which disable system io ranges and do it on their own. 218 */ 219 int acpi_video_display_switch_support(void) 220 { 221 if (!acpi_video_caps_checked) 222 acpi_video_get_capabilities(NULL); 223 224 if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR) 225 return 0; 226 else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO) 227 return 1; 228 229 if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR) 230 return 0; 231 else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO) 232 return 1; 233 234 return acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING; 235 } 236 EXPORT_SYMBOL(acpi_video_display_switch_support); 237 238 /* 239 * Use acpi_display_output=vendor/video or acpi_backlight=vendor/video 240 * To force that backlight or display output switching is processed by vendor 241 * specific acpi drivers or video.ko driver. 242 */ 243 static int __init acpi_backlight(char *str) 244 { 245 if (str == NULL || *str == '\0') 246 return 1; 247 else { 248 if (!strcmp("vendor", str)) 249 acpi_video_support |= 250 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR; 251 if (!strcmp("video", str)) 252 acpi_video_support |= 253 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO; 254 } 255 return 1; 256 } 257 __setup("acpi_backlight=", acpi_backlight); 258 259 static int __init acpi_display_output(char *str) 260 { 261 if (str == NULL || *str == '\0') 262 return 1; 263 else { 264 if (!strcmp("vendor", str)) 265 acpi_video_support |= 266 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR; 267 if (!strcmp("video", str)) 268 acpi_video_support |= 269 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO; 270 } 271 return 1; 272 } 273 __setup("acpi_display_output=", acpi_display_output); 274