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 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 "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 */ 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 /* 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 } 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 /* Force to use vendor driver when the ACPI device is known to be 136 * buggy */ 137 static 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 } 142 143 static 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 */ 169 long 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 } 212 EXPORT_SYMBOL(acpi_video_get_capabilities); 213 214 static 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 */ 230 void acpi_video_dmi_promote_vendor(void) 231 { 232 acpi_video_caps_check(); 233 acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 234 } 235 EXPORT_SYMBOL(acpi_video_dmi_promote_vendor); 236 237 /* To be called when a driver who previously promoted the vendor 238 * interface */ 239 void acpi_video_dmi_demote_vendor(void) 240 { 241 acpi_video_caps_check(); 242 acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 243 } 244 EXPORT_SYMBOL(acpi_video_dmi_demote_vendor); 245 246 /* Returns true if video.ko can do backlight switching */ 247 int 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 } 266 EXPORT_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 */ 272 static 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