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 #include "internal.h" 42 43 #define PREFIX "ACPI: " 44 45 ACPI_MODULE_NAME("video"); 46 #define _COMPONENT ACPI_VIDEO_COMPONENT 47 48 static long acpi_video_support; 49 static bool acpi_video_caps_checked; 50 51 static acpi_status 52 acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context, 53 void **retyurn_value) 54 { 55 long *cap = context; 56 57 if (acpi_has_method(handle, "_BCM") && 58 acpi_has_method(handle, "_BCL")) { 59 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight " 60 "support\n")); 61 *cap |= ACPI_VIDEO_BACKLIGHT; 62 if (!acpi_has_method(handle, "_BQC")) 63 printk(KERN_WARNING FW_BUG PREFIX "No _BQC method, " 64 "cannot determine initial brightness\n"); 65 /* We have backlight support, no need to scan further */ 66 return AE_CTRL_TERMINATE; 67 } 68 return 0; 69 } 70 71 /* Returns true if the ACPI object is a video device which can be 72 * handled by video.ko. 73 * The device will get a Linux specific CID added in scan.c to 74 * identify the device as an ACPI graphics device 75 * Be aware that the graphics device may not be physically present 76 * Use acpi_video_get_capabilities() to detect general ACPI video 77 * capabilities of present cards 78 */ 79 long acpi_is_video_device(acpi_handle handle) 80 { 81 long video_caps = 0; 82 83 /* Is this device able to support video switching ? */ 84 if (acpi_has_method(handle, "_DOD") || acpi_has_method(handle, "_DOS")) 85 video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING; 86 87 /* Is this device able to retrieve a video ROM ? */ 88 if (acpi_has_method(handle, "_ROM")) 89 video_caps |= ACPI_VIDEO_ROM_AVAILABLE; 90 91 /* Is this device able to configure which video head to be POSTed ? */ 92 if (acpi_has_method(handle, "_VPO") && 93 acpi_has_method(handle, "_GPD") && 94 acpi_has_method(handle, "_SPD")) 95 video_caps |= ACPI_VIDEO_DEVICE_POSTING; 96 97 /* Only check for backlight functionality if one of the above hit. */ 98 if (video_caps) 99 acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 100 ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL, 101 &video_caps, NULL); 102 103 return video_caps; 104 } 105 EXPORT_SYMBOL(acpi_is_video_device); 106 107 static acpi_status 108 find_video(acpi_handle handle, u32 lvl, void *context, void **rv) 109 { 110 long *cap = context; 111 struct pci_dev *dev; 112 struct acpi_device *acpi_dev; 113 114 const struct acpi_device_id video_ids[] = { 115 {ACPI_VIDEO_HID, 0}, 116 {"", 0}, 117 }; 118 if (acpi_bus_get_device(handle, &acpi_dev)) 119 return AE_OK; 120 121 if (!acpi_match_device_ids(acpi_dev, video_ids)) { 122 dev = acpi_get_pci_dev(handle); 123 if (!dev) 124 return AE_OK; 125 pci_dev_put(dev); 126 *cap |= acpi_is_video_device(handle); 127 } 128 return AE_OK; 129 } 130 131 /* Force to use vendor driver when the ACPI device is known to be 132 * buggy */ 133 static int video_detect_force_vendor(const struct dmi_system_id *d) 134 { 135 acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 136 return 0; 137 } 138 139 static struct dmi_system_id video_detect_dmi_table[] = { 140 /* On Samsung X360, the BIOS will set a flag (VDRV) if generic 141 * ACPI backlight device is used. This flag will definitively break 142 * the backlight interface (even the vendor interface) untill next 143 * reboot. It's why we should prevent video.ko from being used here 144 * and we can't rely on a later call to acpi_video_unregister(). 145 */ 146 { 147 .callback = video_detect_force_vendor, 148 .ident = "X360", 149 .matches = { 150 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."), 151 DMI_MATCH(DMI_PRODUCT_NAME, "X360"), 152 DMI_MATCH(DMI_BOARD_NAME, "X360"), 153 }, 154 }, 155 { 156 .callback = video_detect_force_vendor, 157 .ident = "Asus UL30VT", 158 .matches = { 159 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."), 160 DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"), 161 }, 162 }, 163 { 164 .callback = video_detect_force_vendor, 165 .ident = "Asus UL30A", 166 .matches = { 167 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."), 168 DMI_MATCH(DMI_PRODUCT_NAME, "UL30A"), 169 }, 170 }, 171 { }, 172 }; 173 174 /* 175 * Returns the video capabilities of a specific ACPI graphics device 176 * 177 * if NULL is passed as argument all ACPI devices are enumerated and 178 * all graphics capabilities of physically present devices are 179 * summarized and returned. This is cached and done only once. 180 */ 181 long acpi_video_get_capabilities(acpi_handle graphics_handle) 182 { 183 long caps = 0; 184 struct acpi_device *tmp_dev; 185 acpi_status status; 186 187 if (acpi_video_caps_checked && graphics_handle == NULL) 188 return acpi_video_support; 189 190 if (!graphics_handle) { 191 /* Only do the global walk through all graphics devices once */ 192 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 193 ACPI_UINT32_MAX, find_video, NULL, 194 &caps, NULL); 195 /* There might be boot param flags set already... */ 196 acpi_video_support |= caps; 197 acpi_video_caps_checked = 1; 198 /* Add blacklists here. Be careful to use the right *DMI* bits 199 * to still be able to override logic via boot params, e.g.: 200 * 201 * if (dmi_name_in_vendors("XY")) { 202 * acpi_video_support |= 203 * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 204 *} 205 */ 206 207 dmi_check_system(video_detect_dmi_table); 208 } else { 209 status = acpi_bus_get_device(graphics_handle, &tmp_dev); 210 if (ACPI_FAILURE(status)) { 211 ACPI_EXCEPTION((AE_INFO, status, "Invalid device")); 212 return 0; 213 } 214 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle, 215 ACPI_UINT32_MAX, find_video, NULL, 216 &caps, NULL); 217 } 218 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n", 219 graphics_handle ? caps : acpi_video_support, 220 graphics_handle ? "on device " : "in general", 221 graphics_handle ? acpi_device_bid(tmp_dev) : "")); 222 return caps; 223 } 224 EXPORT_SYMBOL(acpi_video_get_capabilities); 225 226 static void acpi_video_caps_check(void) 227 { 228 /* 229 * We must check whether the ACPI graphics device is physically plugged 230 * in. Therefore this must be called after binding PCI and ACPI devices 231 */ 232 if (!acpi_video_caps_checked) 233 acpi_video_get_capabilities(NULL); 234 } 235 236 bool acpi_video_backlight_quirks(void) 237 { 238 return acpi_gbl_osi_data >= ACPI_OSI_WIN_8; 239 } 240 EXPORT_SYMBOL(acpi_video_backlight_quirks); 241 242 /* Promote the vendor interface instead of the generic video module. 243 * This function allow DMI blacklists to be implemented by externals 244 * platform drivers instead of putting a big blacklist in video_detect.c 245 * After calling this function you will probably want to call 246 * acpi_video_unregister() to make sure the video module is not loaded 247 */ 248 void acpi_video_dmi_promote_vendor(void) 249 { 250 acpi_video_caps_check(); 251 acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 252 } 253 EXPORT_SYMBOL(acpi_video_dmi_promote_vendor); 254 255 /* To be called when a driver who previously promoted the vendor 256 * interface */ 257 void acpi_video_dmi_demote_vendor(void) 258 { 259 acpi_video_caps_check(); 260 acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 261 } 262 EXPORT_SYMBOL(acpi_video_dmi_demote_vendor); 263 264 /* Returns true if video.ko can do backlight switching */ 265 int acpi_video_backlight_support(void) 266 { 267 acpi_video_caps_check(); 268 269 /* First check for boot param -> highest prio */ 270 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR) 271 return 0; 272 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO) 273 return 1; 274 275 /* Then check for DMI blacklist -> second highest prio */ 276 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR) 277 return 0; 278 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO) 279 return 1; 280 281 /* Then go the default way */ 282 return acpi_video_support & ACPI_VIDEO_BACKLIGHT; 283 } 284 EXPORT_SYMBOL(acpi_video_backlight_support); 285 286 /* 287 * Use acpi_backlight=vendor/video to force that backlight switching 288 * is processed by vendor specific acpi drivers or video.ko driver. 289 */ 290 static int __init acpi_backlight(char *str) 291 { 292 if (str == NULL || *str == '\0') 293 return 1; 294 else { 295 if (!strcmp("vendor", str)) 296 acpi_video_support |= 297 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR; 298 if (!strcmp("video", str)) 299 acpi_video_support |= 300 ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO; 301 } 302 return 1; 303 } 304 __setup("acpi_backlight=", acpi_backlight); 305