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_acpi, 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/acpi.h> 37 #include <linux/dmi.h> 38 #include <linux/pci.h> 39 40 #define PREFIX "ACPI: " 41 42 ACPI_MODULE_NAME("video"); 43 #define _COMPONENT ACPI_VIDEO_COMPONENT 44 45 static long acpi_video_support; 46 static bool acpi_video_caps_checked; 47 48 static acpi_status 49 acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context, 50 void **retyurn_value) 51 { 52 long *cap = context; 53 acpi_handle h_dummy; 54 55 if (ACPI_SUCCESS(acpi_get_handle(handle, "_BCM", &h_dummy)) && 56 ACPI_SUCCESS(acpi_get_handle(handle, "_BCL", &h_dummy))) { 57 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight " 58 "support\n")); 59 *cap |= ACPI_VIDEO_BACKLIGHT; 60 if (ACPI_FAILURE(acpi_get_handle(handle, "_BQC", &h_dummy))) 61 printk(KERN_WARNING FW_BUG PREFIX "No _BQC method, " 62 "cannot determine initial brightness\n"); 63 /* We have backlight support, no need to scan further */ 64 return AE_CTRL_TERMINATE; 65 } 66 return 0; 67 } 68 69 /* Returns true if the device is a video device which can be handled by 70 * video.ko. 71 * The device will get a Linux specific CID added in scan.c to 72 * identify the device as an ACPI graphics device 73 * Be aware that the graphics device may not be physically present 74 * Use acpi_video_get_capabilities() to detect general ACPI video 75 * capabilities of present cards 76 */ 77 long acpi_is_video_device(struct acpi_device *device) 78 { 79 acpi_handle h_dummy; 80 long video_caps = 0; 81 82 if (!device) 83 return 0; 84 85 /* Is this device able to retrieve a video ROM ? */ 86 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy))) 87 video_caps |= ACPI_VIDEO_ROM_AVAILABLE; 88 89 /* Is this device able to configure which video head to be POSTed ? */ 90 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_VPO", &h_dummy)) && 91 ACPI_SUCCESS(acpi_get_handle(device->handle, "_GPD", &h_dummy)) && 92 ACPI_SUCCESS(acpi_get_handle(device->handle, "_SPD", &h_dummy))) 93 video_caps |= ACPI_VIDEO_DEVICE_POSTING; 94 95 /* Only check for backlight functionality if one of the above hit. */ 96 if (video_caps) 97 acpi_walk_namespace(ACPI_TYPE_DEVICE, device->handle, 98 ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL, 99 &video_caps, NULL); 100 101 return video_caps; 102 } 103 EXPORT_SYMBOL(acpi_is_video_device); 104 105 static acpi_status 106 find_video(acpi_handle handle, u32 lvl, void *context, void **rv) 107 { 108 long *cap = context; 109 struct pci_dev *dev; 110 struct acpi_device *acpi_dev; 111 112 const struct acpi_device_id video_ids[] = { 113 {ACPI_VIDEO_HID, 0}, 114 {"", 0}, 115 }; 116 if (acpi_bus_get_device(handle, &acpi_dev)) 117 return AE_OK; 118 119 if (!acpi_match_device_ids(acpi_dev, video_ids)) { 120 dev = acpi_get_pci_dev(handle); 121 if (!dev) 122 return AE_OK; 123 pci_dev_put(dev); 124 *cap |= acpi_is_video_device(acpi_dev); 125 } 126 return AE_OK; 127 } 128 129 /* 130 * Returns the video capabilities of a specific ACPI graphics device 131 * 132 * if NULL is passed as argument all ACPI devices are enumerated and 133 * all graphics capabilities of physically present devices are 134 * summarized and returned. This is cached and done only once. 135 */ 136 long acpi_video_get_capabilities(acpi_handle graphics_handle) 137 { 138 long caps = 0; 139 struct acpi_device *tmp_dev; 140 acpi_status status; 141 142 if (acpi_video_caps_checked && graphics_handle == NULL) 143 return acpi_video_support; 144 145 if (!graphics_handle) { 146 /* Only do the global walk through all graphics devices once */ 147 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 148 ACPI_UINT32_MAX, find_video, NULL, 149 &caps, NULL); 150 /* There might be boot param flags set already... */ 151 acpi_video_support |= caps; 152 acpi_video_caps_checked = 1; 153 /* Add blacklists here. Be careful to use the right *DMI* bits 154 * to still be able to override logic via boot params, e.g.: 155 * 156 * if (dmi_name_in_vendors("XY")) { 157 * acpi_video_support |= 158 * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 159 *} 160 */ 161 } else { 162 status = acpi_bus_get_device(graphics_handle, &tmp_dev); 163 if (ACPI_FAILURE(status)) { 164 ACPI_EXCEPTION((AE_INFO, status, "Invalid device")); 165 return 0; 166 } 167 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle, 168 ACPI_UINT32_MAX, find_video, NULL, 169 &caps, NULL); 170 } 171 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n", 172 graphics_handle ? caps : acpi_video_support, 173 graphics_handle ? "on device " : "in general", 174 graphics_handle ? acpi_device_bid(tmp_dev) : "")); 175 return caps; 176 } 177 EXPORT_SYMBOL(acpi_video_get_capabilities); 178 179 /* Returns true if video.ko can do backlight switching */ 180 int acpi_video_backlight_support(void) 181 { 182 /* 183 * We must check whether the ACPI graphics device is physically plugged 184 * in. Therefore this must be called after binding PCI and ACPI devices 185 */ 186 if (!acpi_video_caps_checked) 187 acpi_video_get_capabilities(NULL); 188 189 /* First check for boot param -> highest prio */ 190 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR) 191 return 0; 192 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO) 193 return 1; 194 195 /* Then check for DMI blacklist -> second highest prio */ 196 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR) 197 return 0; 198 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO) 199 return 1; 200 201 /* Then go the default way */ 202 return acpi_video_support & ACPI_VIDEO_BACKLIGHT; 203 } 204 EXPORT_SYMBOL(acpi_video_backlight_support); 205 206 /* 207 * Use acpi_backlight=vendor/video to force that backlight switching 208 * is processed by vendor specific acpi drivers or video.ko driver. 209 */ 210 static int __init acpi_backlight(char *str) 211 { 212 if (str == NULL || *str == '\0') 213 return 1; 214 else { 215 if (!strcmp("vendor", str)) 216 acpi_video_support |= 217 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR; 218 if (!strcmp("video", str)) 219 acpi_video_support |= 220 ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO; 221 } 222 return 1; 223 } 224 __setup("acpi_backlight=", acpi_backlight); 225