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 if (ACPI_FAILURE(acpi_get_handle(handle, "_BQC", &h_dummy))) 59 printk(KERN_WARNING FW_BUG PREFIX "ACPI brightness " 60 "control misses _BQC function\n"); 61 /* We have backlight support, no need to scan further */ 62 return AE_CTRL_TERMINATE; 63 } 64 return 0; 65 } 66 67 /* Returns true if the device is a video device which can be handled by 68 * video.ko. 69 * The device will get a Linux specific CID added in scan.c to 70 * identify the device as an ACPI graphics device 71 * Be aware that the graphics device may not be physically present 72 * Use acpi_video_get_capabilities() to detect general ACPI video 73 * capabilities of present cards 74 */ 75 long acpi_is_video_device(struct acpi_device *device) 76 { 77 acpi_handle h_dummy; 78 long video_caps = 0; 79 80 if (!device) 81 return 0; 82 83 /* Does this device able to support video switching ? */ 84 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) && 85 ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOS", &h_dummy))) 86 video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING; 87 88 /* Does this device able to retrieve a video ROM ? */ 89 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy))) 90 video_caps |= ACPI_VIDEO_ROM_AVAILABLE; 91 92 /* Does this device able to configure which video head to be POSTed ? */ 93 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_VPO", &h_dummy)) && 94 ACPI_SUCCESS(acpi_get_handle(device->handle, "_GPD", &h_dummy)) && 95 ACPI_SUCCESS(acpi_get_handle(device->handle, "_SPD", &h_dummy))) 96 video_caps |= ACPI_VIDEO_DEVICE_POSTING; 97 98 /* Only check for backlight functionality if one of the above hit. */ 99 if (video_caps) 100 acpi_walk_namespace(ACPI_TYPE_DEVICE, device->handle, 101 ACPI_UINT32_MAX, acpi_backlight_cap_match, 102 &video_caps, NULL); 103 104 return video_caps; 105 } 106 EXPORT_SYMBOL(acpi_is_video_device); 107 108 static acpi_status 109 find_video(acpi_handle handle, u32 lvl, void *context, void **rv) 110 { 111 long *cap = context; 112 struct device *dev; 113 struct acpi_device *acpi_dev; 114 115 const struct acpi_device_id video_ids[] = { 116 {ACPI_VIDEO_HID, 0}, 117 {"", 0}, 118 }; 119 if (acpi_bus_get_device(handle, &acpi_dev)) 120 return AE_OK; 121 122 if (!acpi_match_device_ids(acpi_dev, video_ids)) { 123 dev = acpi_get_physical_pci_device(handle); 124 if (!dev) 125 return AE_OK; 126 put_device(dev); 127 *cap |= acpi_is_video_device(acpi_dev); 128 } 129 return AE_OK; 130 } 131 132 /* 133 * Returns the video capabilities of a specific ACPI graphics device 134 * 135 * if NULL is passed as argument all ACPI devices are enumerated and 136 * all graphics capabilities of physically present devices are 137 * summerized and returned. This is cached and done only once. 138 */ 139 long acpi_video_get_capabilities(acpi_handle graphics_handle) 140 { 141 long caps = 0; 142 struct acpi_device *tmp_dev; 143 acpi_status status; 144 145 if (acpi_video_caps_checked && graphics_handle == NULL) 146 return acpi_video_support; 147 148 if (!graphics_handle) { 149 /* Only do the global walk through all graphics devices once */ 150 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 151 ACPI_UINT32_MAX, find_video, 152 &caps, NULL); 153 /* There might be boot param flags set already... */ 154 acpi_video_support |= caps; 155 acpi_video_caps_checked = 1; 156 /* Add blacklists here. Be careful to use the right *DMI* bits 157 * to still be able to override logic via boot params, e.g.: 158 * 159 * if (dmi_name_in_vendors("XY")) { 160 * acpi_video_support |= 161 * ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR; 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, 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 * Returns true if video.ko can do display output switching. 213 * This does not work well/at all with binary graphics drivers 214 * which disable system io ranges and do it on their own. 215 */ 216 int acpi_video_display_switch_support(void) 217 { 218 if (!acpi_video_caps_checked) 219 acpi_video_get_capabilities(NULL); 220 221 if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR) 222 return 0; 223 else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO) 224 return 1; 225 226 if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR) 227 return 0; 228 else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO) 229 return 1; 230 231 return acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING; 232 } 233 EXPORT_SYMBOL(acpi_video_display_switch_support); 234 235 /* 236 * Use acpi_display_output=vendor/video or acpi_backlight=vendor/video 237 * To force that backlight or display output switching is processed by vendor 238 * specific acpi drivers or video.ko driver. 239 */ 240 static int __init acpi_backlight(char *str) 241 { 242 if (str == NULL || *str == '\0') 243 return 1; 244 else { 245 if (!strcmp("vendor", str)) 246 acpi_video_support |= 247 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR; 248 if (!strcmp("video", str)) 249 acpi_video_support |= 250 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO; 251 } 252 return 1; 253 } 254 __setup("acpi_backlight=", acpi_backlight); 255 256 static int __init acpi_display_output(char *str) 257 { 258 if (str == NULL || *str == '\0') 259 return 1; 260 else { 261 if (!strcmp("vendor", str)) 262 acpi_video_support |= 263 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR; 264 if (!strcmp("video", str)) 265 acpi_video_support |= 266 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO; 267 } 268 return 1; 269 } 270 __setup("acpi_display_output=", acpi_display_output); 271