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 ACPI_MODULE_NAME("video"); 42 #define _COMPONENT ACPI_VIDEO_COMPONENT 43 44 static long acpi_video_support; 45 static bool acpi_video_caps_checked; 46 47 static acpi_status 48 acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context, 49 void **retyurn_value) 50 { 51 long *cap = context; 52 acpi_handle h_dummy; 53 54 if (ACPI_SUCCESS(acpi_get_handle(handle, "_BCM", &h_dummy)) && 55 ACPI_SUCCESS(acpi_get_handle(handle, "_BCL", &h_dummy))) { 56 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight " 57 "support\n")); 58 *cap |= ACPI_VIDEO_BACKLIGHT; 59 if (ACPI_FAILURE(acpi_get_handle(handle, "_BQC", &h_dummy))) 60 printk(KERN_WARNING FW_BUG PREFIX "ACPI brightness " 61 "control misses _BQC function\n"); 62 /* We have backlight support, no need to scan further */ 63 return AE_CTRL_TERMINATE; 64 } 65 return 0; 66 } 67 68 /* Returns true if the device is a video device which can be handled by 69 * video.ko. 70 * The device will get a Linux specific CID added in scan.c to 71 * identify the device as an ACPI graphics device 72 * Be aware that the graphics device may not be physically present 73 * Use acpi_video_get_capabilities() to detect general ACPI video 74 * capabilities of present cards 75 */ 76 long acpi_is_video_device(struct acpi_device *device) 77 { 78 acpi_handle h_dummy; 79 long video_caps = 0; 80 81 if (!device) 82 return 0; 83 84 /* Does this device able to support video switching ? */ 85 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) && 86 ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOS", &h_dummy))) 87 video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING; 88 89 /* Does this device able to retrieve a video ROM ? */ 90 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy))) 91 video_caps |= ACPI_VIDEO_ROM_AVAILABLE; 92 93 /* Does this device able to configure which video head to be POSTed ? */ 94 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_VPO", &h_dummy)) && 95 ACPI_SUCCESS(acpi_get_handle(device->handle, "_GPD", &h_dummy)) && 96 ACPI_SUCCESS(acpi_get_handle(device->handle, "_SPD", &h_dummy))) 97 video_caps |= ACPI_VIDEO_DEVICE_POSTING; 98 99 /* Only check for backlight functionality if one of the above hit. */ 100 if (video_caps) 101 acpi_walk_namespace(ACPI_TYPE_DEVICE, device->handle, 102 ACPI_UINT32_MAX, acpi_backlight_cap_match, 103 &video_caps, NULL); 104 105 return video_caps; 106 } 107 EXPORT_SYMBOL(acpi_is_video_device); 108 109 static acpi_status 110 find_video(acpi_handle handle, u32 lvl, void *context, void **rv) 111 { 112 long *cap = context; 113 struct pci_dev *dev; 114 struct acpi_device *acpi_dev; 115 116 const struct acpi_device_id video_ids[] = { 117 {ACPI_VIDEO_HID, 0}, 118 {"", 0}, 119 }; 120 if (acpi_bus_get_device(handle, &acpi_dev)) 121 return AE_OK; 122 123 if (!acpi_match_device_ids(acpi_dev, video_ids)) { 124 dev = acpi_get_pci_dev(handle); 125 if (!dev) 126 return AE_OK; 127 pci_dev_put(dev); 128 *cap |= acpi_is_video_device(acpi_dev); 129 } 130 return AE_OK; 131 } 132 133 /* 134 * Returns the video capabilities of a specific ACPI graphics device 135 * 136 * if NULL is passed as argument all ACPI devices are enumerated and 137 * all graphics capabilities of physically present devices are 138 * summerized and returned. This is cached and done only once. 139 */ 140 long acpi_video_get_capabilities(acpi_handle graphics_handle) 141 { 142 long caps = 0; 143 struct acpi_device *tmp_dev; 144 acpi_status status; 145 146 if (acpi_video_caps_checked && graphics_handle == NULL) 147 return acpi_video_support; 148 149 if (!graphics_handle) { 150 /* Only do the global walk through all graphics devices once */ 151 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 152 ACPI_UINT32_MAX, find_video, 153 &caps, NULL); 154 /* There might be boot param flags set already... */ 155 acpi_video_support |= caps; 156 acpi_video_caps_checked = 1; 157 /* Add blacklists here. Be careful to use the right *DMI* bits 158 * to still be able to override logic via boot params, e.g.: 159 * 160 * if (dmi_name_in_vendors("XY")) { 161 * acpi_video_support |= 162 * ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR; 163 * acpi_video_support |= 164 * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 165 *} 166 */ 167 } else { 168 status = acpi_bus_get_device(graphics_handle, &tmp_dev); 169 if (ACPI_FAILURE(status)) { 170 ACPI_EXCEPTION((AE_INFO, status, "Invalid device")); 171 return 0; 172 } 173 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle, 174 ACPI_UINT32_MAX, find_video, 175 &caps, NULL); 176 } 177 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n", 178 graphics_handle ? caps : acpi_video_support, 179 graphics_handle ? "on device " : "in general", 180 graphics_handle ? acpi_device_bid(tmp_dev) : "")); 181 return caps; 182 } 183 EXPORT_SYMBOL(acpi_video_get_capabilities); 184 185 /* Returns true if video.ko can do backlight switching */ 186 int acpi_video_backlight_support(void) 187 { 188 /* 189 * We must check whether the ACPI graphics device is physically plugged 190 * in. Therefore this must be called after binding PCI and ACPI devices 191 */ 192 if (!acpi_video_caps_checked) 193 acpi_video_get_capabilities(NULL); 194 195 /* First check for boot param -> highest prio */ 196 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR) 197 return 0; 198 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO) 199 return 1; 200 201 /* Then check for DMI blacklist -> second highest prio */ 202 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR) 203 return 0; 204 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO) 205 return 1; 206 207 /* Then go the default way */ 208 return acpi_video_support & ACPI_VIDEO_BACKLIGHT; 209 } 210 EXPORT_SYMBOL(acpi_video_backlight_support); 211 212 /* 213 * Returns true if video.ko can do display output switching. 214 * This does not work well/at all with binary graphics drivers 215 * which disable system io ranges and do it on their own. 216 */ 217 int acpi_video_display_switch_support(void) 218 { 219 if (!acpi_video_caps_checked) 220 acpi_video_get_capabilities(NULL); 221 222 if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR) 223 return 0; 224 else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO) 225 return 1; 226 227 if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR) 228 return 0; 229 else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO) 230 return 1; 231 232 return acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING; 233 } 234 EXPORT_SYMBOL(acpi_video_display_switch_support); 235 236 /* 237 * Use acpi_display_output=vendor/video or acpi_backlight=vendor/video 238 * To force that backlight or display output switching is processed by vendor 239 * specific acpi drivers or video.ko driver. 240 */ 241 static int __init acpi_backlight(char *str) 242 { 243 if (str == NULL || *str == '\0') 244 return 1; 245 else { 246 if (!strcmp("vendor", str)) 247 acpi_video_support |= 248 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR; 249 if (!strcmp("video", str)) 250 acpi_video_support |= 251 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO; 252 } 253 return 1; 254 } 255 __setup("acpi_backlight=", acpi_backlight); 256 257 static int __init acpi_display_output(char *str) 258 { 259 if (str == NULL || *str == '\0') 260 return 1; 261 else { 262 if (!strcmp("vendor", str)) 263 acpi_video_support |= 264 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR; 265 if (!strcmp("video", str)) 266 acpi_video_support |= 267 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO; 268 } 269 return 1; 270 } 271 __setup("acpi_display_output=", acpi_display_output); 272