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/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 /* 136 * Returns the video capabilities of a specific ACPI graphics device 137 * 138 * if NULL is passed as argument all ACPI devices are enumerated and 139 * all graphics capabilities of physically present devices are 140 * summarized and returned. This is cached and done only once. 141 */ 142 long acpi_video_get_capabilities(acpi_handle graphics_handle) 143 { 144 long caps = 0; 145 struct acpi_device *tmp_dev; 146 acpi_status status; 147 148 if (acpi_video_caps_checked && graphics_handle == NULL) 149 return acpi_video_support; 150 151 if (!graphics_handle) { 152 /* Only do the global walk through all graphics devices once */ 153 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 154 ACPI_UINT32_MAX, find_video, NULL, 155 &caps, NULL); 156 /* There might be boot param flags set already... */ 157 acpi_video_support |= caps; 158 acpi_video_caps_checked = 1; 159 /* Add blacklists here. Be careful to use the right *DMI* bits 160 * to still be able to override logic via boot params, e.g.: 161 * 162 * if (dmi_name_in_vendors("XY")) { 163 * acpi_video_support |= 164 * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR; 165 *} 166 */ 167 } else { 168 status = acpi_bus_get_device(graphics_handle, &tmp_dev); 169 if (ACPI_FAILURE(status)) { 170 ACPI_EXCEPTION((AE_INFO, status, "Invalid device")); 171 return 0; 172 } 173 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle, 174 ACPI_UINT32_MAX, find_video, NULL, 175 &caps, NULL); 176 } 177 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n", 178 graphics_handle ? caps : acpi_video_support, 179 graphics_handle ? "on device " : "in general", 180 graphics_handle ? acpi_device_bid(tmp_dev) : "")); 181 return caps; 182 } 183 EXPORT_SYMBOL(acpi_video_get_capabilities); 184 185 /* Returns true if video.ko can do backlight switching */ 186 int acpi_video_backlight_support(void) 187 { 188 /* 189 * We must check whether the ACPI graphics device is physically plugged 190 * in. Therefore this must be called after binding PCI and ACPI devices 191 */ 192 if (!acpi_video_caps_checked) 193 acpi_video_get_capabilities(NULL); 194 195 /* First check for boot param -> highest prio */ 196 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR) 197 return 0; 198 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO) 199 return 1; 200 201 /* Then check for DMI blacklist -> second highest prio */ 202 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR) 203 return 0; 204 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO) 205 return 1; 206 207 /* Then go the default way */ 208 return acpi_video_support & ACPI_VIDEO_BACKLIGHT; 209 } 210 EXPORT_SYMBOL(acpi_video_backlight_support); 211 212 /* 213 * Use acpi_backlight=vendor/video to force that backlight switching 214 * is processed by vendor specific acpi drivers or video.ko driver. 215 */ 216 static int __init acpi_backlight(char *str) 217 { 218 if (str == NULL || *str == '\0') 219 return 1; 220 else { 221 if (!strcmp("vendor", str)) 222 acpi_video_support |= 223 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR; 224 if (!strcmp("video", str)) 225 acpi_video_support |= 226 ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO; 227 } 228 return 1; 229 } 230 __setup("acpi_backlight=", acpi_backlight); 231