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 ACPI object is a video device which can be 71 * handled by 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(acpi_handle handle) 79 { 80 acpi_handle h_dummy; 81 long video_caps = 0; 82 83 /* Is this device able to support video switching ? */ 84 if (ACPI_SUCCESS(acpi_get_handle(handle, "_DOD", &h_dummy)) || 85 ACPI_SUCCESS(acpi_get_handle(handle, "_DOS", &h_dummy))) 86 video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING; 87 88 /* Is this device able to retrieve a video ROM ? */ 89 if (ACPI_SUCCESS(acpi_get_handle(handle, "_ROM", &h_dummy))) 90 video_caps |= ACPI_VIDEO_ROM_AVAILABLE; 91 92 /* Is this device able to configure which video head to be POSTed ? */ 93 if (ACPI_SUCCESS(acpi_get_handle(handle, "_VPO", &h_dummy)) && 94 ACPI_SUCCESS(acpi_get_handle(handle, "_GPD", &h_dummy)) && 95 ACPI_SUCCESS(acpi_get_handle(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, handle, 101 ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL, 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 pci_dev *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_pci_dev(handle); 124 if (!dev) 125 return AE_OK; 126 pci_dev_put(dev); 127 *cap |= acpi_is_video_device(handle); 128 } 129 return AE_OK; 130 } 131 132 /* Force to use vendor driver when the ACPI device is known to be 133 * buggy */ 134 static int video_detect_force_vendor(const struct dmi_system_id *d) 135 { 136 acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 137 return 0; 138 } 139 140 static struct dmi_system_id video_detect_dmi_table[] = { 141 /* On Samsung X360, the BIOS will set a flag (VDRV) if generic 142 * ACPI backlight device is used. This flag will definitively break 143 * the backlight interface (even the vendor interface) untill next 144 * reboot. It's why we should prevent video.ko from being used here 145 * and we can't rely on a later call to acpi_video_unregister(). 146 */ 147 { 148 .callback = video_detect_force_vendor, 149 .ident = "X360", 150 .matches = { 151 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."), 152 DMI_MATCH(DMI_PRODUCT_NAME, "X360"), 153 DMI_MATCH(DMI_BOARD_NAME, "X360"), 154 }, 155 }, 156 { 157 .callback = video_detect_force_vendor, 158 .ident = "Asus UL30VT", 159 .matches = { 160 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."), 161 DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"), 162 }, 163 }, 164 { }, 165 }; 166 167 /* 168 * Returns the video capabilities of a specific ACPI graphics device 169 * 170 * if NULL is passed as argument all ACPI devices are enumerated and 171 * all graphics capabilities of physically present devices are 172 * summarized and returned. This is cached and done only once. 173 */ 174 long acpi_video_get_capabilities(acpi_handle graphics_handle) 175 { 176 long caps = 0; 177 struct acpi_device *tmp_dev; 178 acpi_status status; 179 180 if (acpi_video_caps_checked && graphics_handle == NULL) 181 return acpi_video_support; 182 183 if (!graphics_handle) { 184 /* Only do the global walk through all graphics devices once */ 185 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 186 ACPI_UINT32_MAX, find_video, NULL, 187 &caps, NULL); 188 /* There might be boot param flags set already... */ 189 acpi_video_support |= caps; 190 acpi_video_caps_checked = 1; 191 /* Add blacklists here. Be careful to use the right *DMI* bits 192 * to still be able to override logic via boot params, e.g.: 193 * 194 * if (dmi_name_in_vendors("XY")) { 195 * acpi_video_support |= 196 * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 197 *} 198 */ 199 200 dmi_check_system(video_detect_dmi_table); 201 } else { 202 status = acpi_bus_get_device(graphics_handle, &tmp_dev); 203 if (ACPI_FAILURE(status)) { 204 ACPI_EXCEPTION((AE_INFO, status, "Invalid device")); 205 return 0; 206 } 207 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle, 208 ACPI_UINT32_MAX, find_video, NULL, 209 &caps, NULL); 210 } 211 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n", 212 graphics_handle ? caps : acpi_video_support, 213 graphics_handle ? "on device " : "in general", 214 graphics_handle ? acpi_device_bid(tmp_dev) : "")); 215 return caps; 216 } 217 EXPORT_SYMBOL(acpi_video_get_capabilities); 218 219 static void acpi_video_caps_check(void) 220 { 221 /* 222 * We must check whether the ACPI graphics device is physically plugged 223 * in. Therefore this must be called after binding PCI and ACPI devices 224 */ 225 if (!acpi_video_caps_checked) 226 acpi_video_get_capabilities(NULL); 227 } 228 229 /* Promote the vendor interface instead of the generic video module. 230 * This function allow DMI blacklists to be implemented by externals 231 * platform drivers instead of putting a big blacklist in video_detect.c 232 * After calling this function you will probably want to call 233 * acpi_video_unregister() to make sure the video module is not loaded 234 */ 235 void acpi_video_dmi_promote_vendor(void) 236 { 237 acpi_video_caps_check(); 238 acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 239 } 240 EXPORT_SYMBOL(acpi_video_dmi_promote_vendor); 241 242 /* To be called when a driver who previously promoted the vendor 243 * interface */ 244 void acpi_video_dmi_demote_vendor(void) 245 { 246 acpi_video_caps_check(); 247 acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 248 } 249 EXPORT_SYMBOL(acpi_video_dmi_demote_vendor); 250 251 /* Returns true if video.ko can do backlight switching */ 252 int acpi_video_backlight_support(void) 253 { 254 acpi_video_caps_check(); 255 256 /* First check for boot param -> highest prio */ 257 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR) 258 return 0; 259 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO) 260 return 1; 261 262 /* Then check for DMI blacklist -> second highest prio */ 263 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR) 264 return 0; 265 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO) 266 return 1; 267 268 /* Then go the default way */ 269 return acpi_video_support & ACPI_VIDEO_BACKLIGHT; 270 } 271 EXPORT_SYMBOL(acpi_video_backlight_support); 272 273 /* 274 * Use acpi_backlight=vendor/video to force that backlight switching 275 * is processed by vendor specific acpi drivers or video.ko driver. 276 */ 277 static int __init acpi_backlight(char *str) 278 { 279 if (str == NULL || *str == '\0') 280 return 1; 281 else { 282 if (!strcmp("vendor", str)) 283 acpi_video_support |= 284 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR; 285 if (!strcmp("video", str)) 286 acpi_video_support |= 287 ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO; 288 } 289 return 1; 290 } 291 __setup("acpi_backlight=", acpi_backlight); 292