1/* 2 * vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs 3 * 4 * Copyright (c) 2010 Red Hat Inc. 5 * Author : Dave Airlie <airlied@redhat.com> 6 * 7 * Copyright (c) 2015 Lukas Wunner <lukas@wunner.de> 8 * 9 * Permission is hereby granted, free of charge, to any person obtaining a 10 * copy of this software and associated documentation files (the "Software"), 11 * to deal in the Software without restriction, including without limitation 12 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 13 * and/or sell copies of the Software, and to permit persons to whom the 14 * Software is furnished to do so, subject to the following conditions: 15 * 16 * The above copyright notice and this permission notice (including the next 17 * paragraph) shall be included in all copies or substantial portions of the 18 * Software. 19 * 20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 23 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 25 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 26 * DEALINGS 27 * IN THE SOFTWARE. 28 * 29 */ 30 31#define pr_fmt(fmt) "vga_switcheroo: " fmt 32 33#include <linux/apple-gmux.h> 34#include <linux/console.h> 35#include <linux/debugfs.h> 36#include <linux/fb.h> 37#include <linux/fs.h> 38#include <linux/fbcon.h> 39#include <linux/module.h> 40#include <linux/pci.h> 41#include <linux/pm_domain.h> 42#include <linux/pm_runtime.h> 43#include <linux/seq_file.h> 44#include <linux/uaccess.h> 45#include <linux/vgaarb.h> 46#include <linux/vga_switcheroo.h> 47 48/** 49 * DOC: Overview 50 * 51 * vga_switcheroo is the Linux subsystem for laptop hybrid graphics. 52 * These come in two flavors: 53 * 54 * * muxed: Dual GPUs with a multiplexer chip to switch outputs between GPUs. 55 * * muxless: Dual GPUs but only one of them is connected to outputs. 56 * The other one is merely used to offload rendering, its results 57 * are copied over PCIe into the framebuffer. On Linux this is 58 * supported with DRI PRIME. 59 * 60 * Hybrid graphics started to appear in the late Naughties and were initially 61 * all muxed. Newer laptops moved to a muxless architecture for cost reasons. 62 * A notable exception is the MacBook Pro which continues to use a mux. 63 * Muxes come with varying capabilities: Some switch only the panel, others 64 * can also switch external displays. Some switch all display pins at once 65 * while others can switch just the DDC lines. (To allow EDID probing 66 * for the inactive GPU.) Also, muxes are often used to cut power to the 67 * discrete GPU while it is not used. 68 * 69 * DRM drivers register GPUs with vga_switcheroo, these are henceforth called 70 * clients. The mux is called the handler. Muxless machines also register a 71 * handler to control the power state of the discrete GPU, its ->switchto 72 * callback is a no-op for obvious reasons. The discrete GPU is often equipped 73 * with an HDA controller for the HDMI/DP audio signal, this will also 74 * register as a client so that vga_switcheroo can take care of the correct 75 * suspend/resume order when changing the discrete GPU's power state. In total 76 * there can thus be up to three clients: Two vga clients (GPUs) and one audio 77 * client (on the discrete GPU). The code is mostly prepared to support 78 * machines with more than two GPUs should they become available. 79 * 80 * The GPU to which the outputs are currently switched is called the 81 * active client in vga_switcheroo parlance. The GPU not in use is the 82 * inactive client. When the inactive client's DRM driver is loaded, 83 * it will be unable to probe the panel's EDID and hence depends on 84 * VBIOS to provide its display modes. If the VBIOS modes are bogus or 85 * if there is no VBIOS at all (which is common on the MacBook Pro), 86 * a client may alternatively request that the DDC lines are temporarily 87 * switched to it, provided that the handler supports this. Switching 88 * only the DDC lines and not the entire output avoids unnecessary 89 * flickering. 90 */ 91 92/** 93 * struct vga_switcheroo_client - registered client 94 * @pdev: client pci device 95 * @fb_info: framebuffer to which console is remapped on switching 96 * @pwr_state: current power state if manual power control is used. 97 * For driver power control, call vga_switcheroo_pwr_state(). 98 * @ops: client callbacks 99 * @id: client identifier. Determining the id requires the handler, 100 * so gpus are initially assigned VGA_SWITCHEROO_UNKNOWN_ID 101 * and later given their true id in vga_switcheroo_enable() 102 * @active: whether the outputs are currently switched to this client 103 * @driver_power_control: whether power state is controlled by the driver's 104 * runtime pm. If true, writing ON and OFF to the vga_switcheroo debugfs 105 * interface is a no-op so as not to interfere with runtime pm 106 * @list: client list 107 * @vga_dev: pci device, indicate which GPU is bound to current audio client 108 * 109 * Registered client. A client can be either a GPU or an audio device on a GPU. 110 * For audio clients, the @fb_info and @active members are bogus. For GPU 111 * clients, the @vga_dev is bogus. 112 */ 113struct vga_switcheroo_client { 114 struct pci_dev *pdev; 115 struct fb_info *fb_info; 116 enum vga_switcheroo_state pwr_state; 117 const struct vga_switcheroo_client_ops *ops; 118 enum vga_switcheroo_client_id id; 119 bool active; 120 bool driver_power_control; 121 struct list_head list; 122 struct pci_dev *vga_dev; 123}; 124 125/* 126 * protects access to struct vgasr_priv 127 */ 128static DEFINE_MUTEX(vgasr_mutex); 129 130/** 131 * struct vgasr_priv - vga_switcheroo private data 132 * @active: whether vga_switcheroo is enabled. 133 * Prerequisite is the registration of two GPUs and a handler 134 * @delayed_switch_active: whether a delayed switch is pending 135 * @delayed_client_id: client to which a delayed switch is pending 136 * @debugfs_root: directory for vga_switcheroo debugfs interface 137 * @registered_clients: number of registered GPUs 138 * (counting only vga clients, not audio clients) 139 * @clients: list of registered clients 140 * @handler: registered handler 141 * @handler_flags: flags of registered handler 142 * @mux_hw_lock: protects mux state 143 * (in particular while DDC lines are temporarily switched) 144 * @old_ddc_owner: client to which DDC lines will be switched back on unlock 145 * 146 * vga_switcheroo private data. Currently only one vga_switcheroo instance 147 * per system is supported. 148 */ 149struct vgasr_priv { 150 bool active; 151 bool delayed_switch_active; 152 enum vga_switcheroo_client_id delayed_client_id; 153 154 struct dentry *debugfs_root; 155 156 int registered_clients; 157 struct list_head clients; 158 159 const struct vga_switcheroo_handler *handler; 160 enum vga_switcheroo_handler_flags_t handler_flags; 161 struct mutex mux_hw_lock; 162 int old_ddc_owner; 163}; 164 165#define ID_BIT_AUDIO 0x100 166#define client_is_audio(c) ((c)->id & ID_BIT_AUDIO) 167#define client_is_vga(c) (!client_is_audio(c)) 168#define client_id(c) ((c)->id & ~ID_BIT_AUDIO) 169 170static void vga_switcheroo_debugfs_init(struct vgasr_priv *priv); 171static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv); 172 173/* only one switcheroo per system */ 174static struct vgasr_priv vgasr_priv = { 175 .clients = LIST_HEAD_INIT(vgasr_priv.clients), 176 .mux_hw_lock = __MUTEX_INITIALIZER(vgasr_priv.mux_hw_lock), 177}; 178 179static bool vga_switcheroo_ready(void) 180{ 181 /* we're ready if we get two clients + handler */ 182 return !vgasr_priv.active && 183 vgasr_priv.registered_clients == 2 && vgasr_priv.handler; 184} 185 186static void vga_switcheroo_enable(void) 187{ 188 int ret; 189 struct vga_switcheroo_client *client; 190 191 /* call the handler to init */ 192 if (vgasr_priv.handler->init) 193 vgasr_priv.handler->init(); 194 195 list_for_each_entry(client, &vgasr_priv.clients, list) { 196 if (!client_is_vga(client) || 197 client_id(client) != VGA_SWITCHEROO_UNKNOWN_ID) 198 continue; 199 200 ret = vgasr_priv.handler->get_client_id(client->pdev); 201 if (ret < 0) 202 return; 203 204 client->id = ret; 205 } 206 207 list_for_each_entry(client, &vgasr_priv.clients, list) { 208 if (!client_is_audio(client) || 209 client_id(client) != VGA_SWITCHEROO_UNKNOWN_ID) 210 continue; 211 212 ret = vgasr_priv.handler->get_client_id(client->vga_dev); 213 if (ret < 0) 214 return; 215 216 client->id = ret | ID_BIT_AUDIO; 217 if (client->ops->gpu_bound) 218 client->ops->gpu_bound(client->pdev, ret); 219 } 220 221 vga_switcheroo_debugfs_init(&vgasr_priv); 222 vgasr_priv.active = true; 223} 224 225/** 226 * vga_switcheroo_register_handler() - register handler 227 * @handler: handler callbacks 228 * @handler_flags: handler flags 229 * 230 * Register handler. Enable vga_switcheroo if two vga clients have already 231 * registered. 232 * 233 * Return: 0 on success, -EINVAL if a handler was already registered. 234 */ 235int vga_switcheroo_register_handler( 236 const struct vga_switcheroo_handler *handler, 237 enum vga_switcheroo_handler_flags_t handler_flags) 238{ 239 mutex_lock(&vgasr_mutex); 240 if (vgasr_priv.handler) { 241 mutex_unlock(&vgasr_mutex); 242 return -EINVAL; 243 } 244 245 vgasr_priv.handler = handler; 246 vgasr_priv.handler_flags = handler_flags; 247 if (vga_switcheroo_ready()) { 248 pr_info("enabled\n"); 249 vga_switcheroo_enable(); 250 } 251 mutex_unlock(&vgasr_mutex); 252 return 0; 253} 254EXPORT_SYMBOL(vga_switcheroo_register_handler); 255 256/** 257 * vga_switcheroo_unregister_handler() - unregister handler 258 * 259 * Unregister handler. Disable vga_switcheroo. 260 */ 261void vga_switcheroo_unregister_handler(void) 262{ 263 mutex_lock(&vgasr_mutex); 264 mutex_lock(&vgasr_priv.mux_hw_lock); 265 vgasr_priv.handler_flags = 0; 266 vgasr_priv.handler = NULL; 267 if (vgasr_priv.active) { 268 pr_info("disabled\n"); 269 vga_switcheroo_debugfs_fini(&vgasr_priv); 270 vgasr_priv.active = false; 271 } 272 mutex_unlock(&vgasr_priv.mux_hw_lock); 273 mutex_unlock(&vgasr_mutex); 274} 275EXPORT_SYMBOL(vga_switcheroo_unregister_handler); 276 277/** 278 * vga_switcheroo_handler_flags() - obtain handler flags 279 * 280 * Helper for clients to obtain the handler flags bitmask. 281 * 282 * Return: Handler flags. A value of 0 means that no handler is registered 283 * or that the handler has no special capabilities. 284 */ 285enum vga_switcheroo_handler_flags_t vga_switcheroo_handler_flags(void) 286{ 287 return vgasr_priv.handler_flags; 288} 289EXPORT_SYMBOL(vga_switcheroo_handler_flags); 290 291static int register_client(struct pci_dev *pdev, 292 const struct vga_switcheroo_client_ops *ops, 293 enum vga_switcheroo_client_id id, 294 struct pci_dev *vga_dev, 295 bool active, 296 bool driver_power_control) 297{ 298 struct vga_switcheroo_client *client; 299 300 client = kzalloc(sizeof(*client), GFP_KERNEL); 301 if (!client) 302 return -ENOMEM; 303 304 client->pwr_state = VGA_SWITCHEROO_ON; 305 client->pdev = pdev; 306 client->ops = ops; 307 client->id = id; 308 client->active = active; 309 client->driver_power_control = driver_power_control; 310 client->vga_dev = vga_dev; 311 312 mutex_lock(&vgasr_mutex); 313 list_add_tail(&client->list, &vgasr_priv.clients); 314 if (client_is_vga(client)) 315 vgasr_priv.registered_clients++; 316 317 if (vga_switcheroo_ready()) { 318 pr_info("enabled\n"); 319 vga_switcheroo_enable(); 320 } 321 mutex_unlock(&vgasr_mutex); 322 return 0; 323} 324 325/** 326 * vga_switcheroo_register_client - register vga client 327 * @pdev: client pci device 328 * @ops: client callbacks 329 * @driver_power_control: whether power state is controlled by the driver's 330 * runtime pm 331 * 332 * Register vga client (GPU). Enable vga_switcheroo if another GPU and a 333 * handler have already registered. The power state of the client is assumed 334 * to be ON. Beforehand, vga_switcheroo_client_probe_defer() shall be called 335 * to ensure that all prerequisites are met. 336 * 337 * Return: 0 on success, -ENOMEM on memory allocation error. 338 */ 339int vga_switcheroo_register_client(struct pci_dev *pdev, 340 const struct vga_switcheroo_client_ops *ops, 341 bool driver_power_control) 342{ 343 return register_client(pdev, ops, VGA_SWITCHEROO_UNKNOWN_ID, NULL, 344 pdev == vga_default_device(), 345 driver_power_control); 346} 347EXPORT_SYMBOL(vga_switcheroo_register_client); 348 349/** 350 * vga_switcheroo_register_audio_client - register audio client 351 * @pdev: client pci device 352 * @ops: client callbacks 353 * @vga_dev: pci device which is bound to current audio client 354 * 355 * Register audio client (audio device on a GPU). The client is assumed 356 * to use runtime PM. Beforehand, vga_switcheroo_client_probe_defer() 357 * shall be called to ensure that all prerequisites are met. 358 * 359 * Return: 0 on success, -ENOMEM on memory allocation error, -EINVAL on getting 360 * client id error. 361 */ 362int vga_switcheroo_register_audio_client(struct pci_dev *pdev, 363 const struct vga_switcheroo_client_ops *ops, 364 struct pci_dev *vga_dev) 365{ 366 enum vga_switcheroo_client_id id = VGA_SWITCHEROO_UNKNOWN_ID; 367 368 /* 369 * if vga_switcheroo has enabled, that mean two GPU clients and also 370 * handler are registered. Get audio client id from bound GPU client 371 * id directly, otherwise, set it as VGA_SWITCHEROO_UNKNOWN_ID, 372 * it will set to correct id in later when vga_switcheroo_enable() 373 * is called. 374 */ 375 mutex_lock(&vgasr_mutex); 376 if (vgasr_priv.active) { 377 id = vgasr_priv.handler->get_client_id(vga_dev); 378 if (id < 0) { 379 mutex_unlock(&vgasr_mutex); 380 return -EINVAL; 381 } 382 /* notify if GPU has been already bound */ 383 if (ops->gpu_bound) 384 ops->gpu_bound(pdev, id); 385 } 386 mutex_unlock(&vgasr_mutex); 387 388 return register_client(pdev, ops, id | ID_BIT_AUDIO, vga_dev, 389 false, true); 390} 391EXPORT_SYMBOL(vga_switcheroo_register_audio_client); 392 393static struct vga_switcheroo_client * 394find_client_from_pci(struct list_head *head, struct pci_dev *pdev) 395{ 396 struct vga_switcheroo_client *client; 397 398 list_for_each_entry(client, head, list) 399 if (client->pdev == pdev) 400 return client; 401 return NULL; 402} 403 404static struct vga_switcheroo_client * 405find_client_from_id(struct list_head *head, 406 enum vga_switcheroo_client_id client_id) 407{ 408 struct vga_switcheroo_client *client; 409 410 list_for_each_entry(client, head, list) 411 if (client->id == client_id) 412 return client; 413 return NULL; 414} 415 416static struct vga_switcheroo_client * 417find_active_client(struct list_head *head) 418{ 419 struct vga_switcheroo_client *client; 420 421 list_for_each_entry(client, head, list) 422 if (client->active) 423 return client; 424 return NULL; 425} 426 427/** 428 * vga_switcheroo_client_probe_defer() - whether to defer probing a given client 429 * @pdev: client pci device 430 * 431 * Determine whether any prerequisites are not fulfilled to probe a given 432 * client. Drivers shall invoke this early on in their ->probe callback 433 * and return %-EPROBE_DEFER if it evaluates to %true. Thou shalt not 434 * register the client ere thou hast called this. 435 * 436 * Return: %true if probing should be deferred, otherwise %false. 437 */ 438bool vga_switcheroo_client_probe_defer(struct pci_dev *pdev) 439{ 440 if ((pdev->class >> 16) == PCI_BASE_CLASS_DISPLAY) { 441 /* 442 * apple-gmux is needed on pre-retina MacBook Pro 443 * to probe the panel if pdev is the inactive GPU. 444 */ 445 if (apple_gmux_present() && pdev != vga_default_device() && 446 !vgasr_priv.handler_flags) 447 return true; 448 } 449 450 return false; 451} 452EXPORT_SYMBOL(vga_switcheroo_client_probe_defer); 453 454static enum vga_switcheroo_state 455vga_switcheroo_pwr_state(struct vga_switcheroo_client *client) 456{ 457 if (client->driver_power_control) 458 if (pm_runtime_enabled(&client->pdev->dev) && 459 pm_runtime_active(&client->pdev->dev)) 460 return VGA_SWITCHEROO_ON; 461 else 462 return VGA_SWITCHEROO_OFF; 463 else 464 return client->pwr_state; 465} 466 467/** 468 * vga_switcheroo_get_client_state() - obtain power state of a given client 469 * @pdev: client pci device 470 * 471 * Obtain power state of a given client as seen from vga_switcheroo. 472 * The function is only called from hda_intel.c. 473 * 474 * Return: Power state. 475 */ 476enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *pdev) 477{ 478 struct vga_switcheroo_client *client; 479 enum vga_switcheroo_state ret; 480 481 mutex_lock(&vgasr_mutex); 482 client = find_client_from_pci(&vgasr_priv.clients, pdev); 483 if (!client) 484 ret = VGA_SWITCHEROO_NOT_FOUND; 485 else 486 ret = vga_switcheroo_pwr_state(client); 487 mutex_unlock(&vgasr_mutex); 488 return ret; 489} 490EXPORT_SYMBOL(vga_switcheroo_get_client_state); 491 492/** 493 * vga_switcheroo_unregister_client() - unregister client 494 * @pdev: client pci device 495 * 496 * Unregister client. Disable vga_switcheroo if this is a vga client (GPU). 497 */ 498void vga_switcheroo_unregister_client(struct pci_dev *pdev) 499{ 500 struct vga_switcheroo_client *client; 501 502 mutex_lock(&vgasr_mutex); 503 client = find_client_from_pci(&vgasr_priv.clients, pdev); 504 if (client) { 505 if (client_is_vga(client)) 506 vgasr_priv.registered_clients--; 507 list_del(&client->list); 508 kfree(client); 509 } 510 if (vgasr_priv.active && vgasr_priv.registered_clients < 2) { 511 pr_info("disabled\n"); 512 vga_switcheroo_debugfs_fini(&vgasr_priv); 513 vgasr_priv.active = false; 514 } 515 mutex_unlock(&vgasr_mutex); 516} 517EXPORT_SYMBOL(vga_switcheroo_unregister_client); 518 519/** 520 * vga_switcheroo_client_fb_set() - set framebuffer of a given client 521 * @pdev: client pci device 522 * @info: framebuffer 523 * 524 * Set framebuffer of a given client. The console will be remapped to this 525 * on switching. 526 */ 527void vga_switcheroo_client_fb_set(struct pci_dev *pdev, 528 struct fb_info *info) 529{ 530 struct vga_switcheroo_client *client; 531 532 mutex_lock(&vgasr_mutex); 533 client = find_client_from_pci(&vgasr_priv.clients, pdev); 534 if (client) 535 client->fb_info = info; 536 mutex_unlock(&vgasr_mutex); 537} 538EXPORT_SYMBOL(vga_switcheroo_client_fb_set); 539 540/** 541 * vga_switcheroo_lock_ddc() - temporarily switch DDC lines to a given client 542 * @pdev: client pci device 543 * 544 * Temporarily switch DDC lines to the client identified by @pdev 545 * (but leave the outputs otherwise switched to where they are). 546 * This allows the inactive client to probe EDID. The DDC lines must 547 * afterwards be switched back by calling vga_switcheroo_unlock_ddc(), 548 * even if this function returns an error. 549 * 550 * Return: Previous DDC owner on success or a negative int on error. 551 * Specifically, %-ENODEV if no handler has registered or if the handler 552 * does not support switching the DDC lines. Also, a negative value 553 * returned by the handler is propagated back to the caller. 554 * The return value has merely an informational purpose for any caller 555 * which might be interested in it. It is acceptable to ignore the return 556 * value and simply rely on the result of the subsequent EDID probe, 557 * which will be %NULL if DDC switching failed. 558 */ 559int vga_switcheroo_lock_ddc(struct pci_dev *pdev) 560{ 561 enum vga_switcheroo_client_id id; 562 563 mutex_lock(&vgasr_priv.mux_hw_lock); 564 if (!vgasr_priv.handler || !vgasr_priv.handler->switch_ddc) { 565 vgasr_priv.old_ddc_owner = -ENODEV; 566 return -ENODEV; 567 } 568 569 id = vgasr_priv.handler->get_client_id(pdev); 570 vgasr_priv.old_ddc_owner = vgasr_priv.handler->switch_ddc(id); 571 return vgasr_priv.old_ddc_owner; 572} 573EXPORT_SYMBOL(vga_switcheroo_lock_ddc); 574 575/** 576 * vga_switcheroo_unlock_ddc() - switch DDC lines back to previous owner 577 * @pdev: client pci device 578 * 579 * Switch DDC lines back to the previous owner after calling 580 * vga_switcheroo_lock_ddc(). This must be called even if 581 * vga_switcheroo_lock_ddc() returned an error. 582 * 583 * Return: Previous DDC owner on success (i.e. the client identifier of @pdev) 584 * or a negative int on error. 585 * Specifically, %-ENODEV if no handler has registered or if the handler 586 * does not support switching the DDC lines. Also, a negative value 587 * returned by the handler is propagated back to the caller. 588 * Finally, invoking this function without calling vga_switcheroo_lock_ddc() 589 * first is not allowed and will result in %-EINVAL. 590 */ 591int vga_switcheroo_unlock_ddc(struct pci_dev *pdev) 592{ 593 enum vga_switcheroo_client_id id; 594 int ret = vgasr_priv.old_ddc_owner; 595 596 if (WARN_ON_ONCE(!mutex_is_locked(&vgasr_priv.mux_hw_lock))) 597 return -EINVAL; 598 599 if (vgasr_priv.old_ddc_owner >= 0) { 600 id = vgasr_priv.handler->get_client_id(pdev); 601 if (vgasr_priv.old_ddc_owner != id) 602 ret = vgasr_priv.handler->switch_ddc( 603 vgasr_priv.old_ddc_owner); 604 } 605 mutex_unlock(&vgasr_priv.mux_hw_lock); 606 return ret; 607} 608EXPORT_SYMBOL(vga_switcheroo_unlock_ddc); 609 610/** 611 * DOC: Manual switching and manual power control 612 * 613 * In this mode of use, the file /sys/kernel/debug/vgaswitcheroo/switch 614 * can be read to retrieve the current vga_switcheroo state and commands 615 * can be written to it to change the state. The file appears as soon as 616 * two GPU drivers and one handler have registered with vga_switcheroo. 617 * The following commands are understood: 618 * 619 * * OFF: Power off the device not in use. 620 * * ON: Power on the device not in use. 621 * * IGD: Switch to the integrated graphics device. 622 * Power on the integrated GPU if necessary, power off the discrete GPU. 623 * Prerequisite is that no user space processes (e.g. Xorg, alsactl) 624 * have opened device files of the GPUs or the audio client. If the 625 * switch fails, the user may invoke lsof(8) or fuser(1) on /dev/dri/ 626 * and /dev/snd/controlC1 to identify processes blocking the switch. 627 * * DIS: Switch to the discrete graphics device. 628 * * DIGD: Delayed switch to the integrated graphics device. 629 * This will perform the switch once the last user space process has 630 * closed the device files of the GPUs and the audio client. 631 * * DDIS: Delayed switch to the discrete graphics device. 632 * * MIGD: Mux-only switch to the integrated graphics device. 633 * Does not remap console or change the power state of either gpu. 634 * If the integrated GPU is currently off, the screen will turn black. 635 * If it is on, the screen will show whatever happens to be in VRAM. 636 * Either way, the user has to blindly enter the command to switch back. 637 * * MDIS: Mux-only switch to the discrete graphics device. 638 * 639 * For GPUs whose power state is controlled by the driver's runtime pm, 640 * the ON and OFF commands are a no-op (see next section). 641 * 642 * For muxless machines, the IGD/DIS, DIGD/DDIS and MIGD/MDIS commands 643 * should not be used. 644 */ 645 646static int vga_switcheroo_show(struct seq_file *m, void *v) 647{ 648 struct vga_switcheroo_client *client; 649 int i = 0; 650 651 mutex_lock(&vgasr_mutex); 652 list_for_each_entry(client, &vgasr_priv.clients, list) { 653 seq_printf(m, "%d:%s%s:%c:%s%s:%s\n", i, 654 client_id(client) == VGA_SWITCHEROO_DIS ? "DIS" : 655 "IGD", 656 client_is_vga(client) ? "" : "-Audio", 657 client->active ? '+' : ' ', 658 client->driver_power_control ? "Dyn" : "", 659 vga_switcheroo_pwr_state(client) ? "Pwr" : "Off", 660 pci_name(client->pdev)); 661 i++; 662 } 663 mutex_unlock(&vgasr_mutex); 664 return 0; 665} 666 667static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file) 668{ 669 return single_open(file, vga_switcheroo_show, NULL); 670} 671 672static int vga_switchon(struct vga_switcheroo_client *client) 673{ 674 if (client->driver_power_control) 675 return 0; 676 if (vgasr_priv.handler->power_state) 677 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON); 678 /* call the driver callback to turn on device */ 679 client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON); 680 client->pwr_state = VGA_SWITCHEROO_ON; 681 return 0; 682} 683 684static int vga_switchoff(struct vga_switcheroo_client *client) 685{ 686 if (client->driver_power_control) 687 return 0; 688 /* call the driver callback to turn off device */ 689 client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF); 690 if (vgasr_priv.handler->power_state) 691 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF); 692 client->pwr_state = VGA_SWITCHEROO_OFF; 693 return 0; 694} 695 696static void set_audio_state(enum vga_switcheroo_client_id id, 697 enum vga_switcheroo_state state) 698{ 699 struct vga_switcheroo_client *client; 700 701 client = find_client_from_id(&vgasr_priv.clients, id | ID_BIT_AUDIO); 702 if (client) 703 client->ops->set_gpu_state(client->pdev, state); 704} 705 706/* stage one happens before delay */ 707static int vga_switchto_stage1(struct vga_switcheroo_client *new_client) 708{ 709 struct vga_switcheroo_client *active; 710 711 active = find_active_client(&vgasr_priv.clients); 712 if (!active) 713 return 0; 714 715 if (vga_switcheroo_pwr_state(new_client) == VGA_SWITCHEROO_OFF) 716 vga_switchon(new_client); 717 718 vga_set_default_device(new_client->pdev); 719 return 0; 720} 721 722/* post delay */ 723static int vga_switchto_stage2(struct vga_switcheroo_client *new_client) 724{ 725 int ret; 726 struct vga_switcheroo_client *active; 727 728 active = find_active_client(&vgasr_priv.clients); 729 if (!active) 730 return 0; 731 732 active->active = false; 733 734 /* let HDA controller autosuspend if GPU uses driver power control */ 735 if (!active->driver_power_control) 736 set_audio_state(active->id, VGA_SWITCHEROO_OFF); 737 738 if (new_client->fb_info) 739 fbcon_remap_all(new_client->fb_info); 740 741 mutex_lock(&vgasr_priv.mux_hw_lock); 742 ret = vgasr_priv.handler->switchto(new_client->id); 743 mutex_unlock(&vgasr_priv.mux_hw_lock); 744 if (ret) 745 return ret; 746 747 if (new_client->ops->reprobe) 748 new_client->ops->reprobe(new_client->pdev); 749 750 if (vga_switcheroo_pwr_state(active) == VGA_SWITCHEROO_ON) 751 vga_switchoff(active); 752 753 /* let HDA controller autoresume if GPU uses driver power control */ 754 if (!new_client->driver_power_control) 755 set_audio_state(new_client->id, VGA_SWITCHEROO_ON); 756 757 new_client->active = true; 758 return 0; 759} 760 761static bool check_can_switch(void) 762{ 763 struct vga_switcheroo_client *client; 764 765 list_for_each_entry(client, &vgasr_priv.clients, list) { 766 if (!client->ops->can_switch(client->pdev)) { 767 pr_err("client %x refused switch\n", client->id); 768 return false; 769 } 770 } 771 return true; 772} 773 774static ssize_t 775vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf, 776 size_t cnt, loff_t *ppos) 777{ 778 char usercmd[64]; 779 int ret; 780 bool delay = false, can_switch; 781 bool just_mux = false; 782 enum vga_switcheroo_client_id client_id = VGA_SWITCHEROO_UNKNOWN_ID; 783 struct vga_switcheroo_client *client = NULL; 784 785 if (cnt > 63) 786 cnt = 63; 787 788 if (copy_from_user(usercmd, ubuf, cnt)) 789 return -EFAULT; 790 791 mutex_lock(&vgasr_mutex); 792 793 if (!vgasr_priv.active) { 794 cnt = -EINVAL; 795 goto out; 796 } 797 798 /* pwr off the device not in use */ 799 if (strncmp(usercmd, "OFF", 3) == 0) { 800 list_for_each_entry(client, &vgasr_priv.clients, list) { 801 if (client->active || client_is_audio(client)) 802 continue; 803 if (client->driver_power_control) 804 continue; 805 set_audio_state(client->id, VGA_SWITCHEROO_OFF); 806 if (client->pwr_state == VGA_SWITCHEROO_ON) 807 vga_switchoff(client); 808 } 809 goto out; 810 } 811 /* pwr on the device not in use */ 812 if (strncmp(usercmd, "ON", 2) == 0) { 813 list_for_each_entry(client, &vgasr_priv.clients, list) { 814 if (client->active || client_is_audio(client)) 815 continue; 816 if (client->driver_power_control) 817 continue; 818 if (client->pwr_state == VGA_SWITCHEROO_OFF) 819 vga_switchon(client); 820 set_audio_state(client->id, VGA_SWITCHEROO_ON); 821 } 822 goto out; 823 } 824 825 /* request a delayed switch - test can we switch now */ 826 if (strncmp(usercmd, "DIGD", 4) == 0) { 827 client_id = VGA_SWITCHEROO_IGD; 828 delay = true; 829 } 830 831 if (strncmp(usercmd, "DDIS", 4) == 0) { 832 client_id = VGA_SWITCHEROO_DIS; 833 delay = true; 834 } 835 836 if (strncmp(usercmd, "IGD", 3) == 0) 837 client_id = VGA_SWITCHEROO_IGD; 838 839 if (strncmp(usercmd, "DIS", 3) == 0) 840 client_id = VGA_SWITCHEROO_DIS; 841 842 if (strncmp(usercmd, "MIGD", 4) == 0) { 843 just_mux = true; 844 client_id = VGA_SWITCHEROO_IGD; 845 } 846 if (strncmp(usercmd, "MDIS", 4) == 0) { 847 just_mux = true; 848 client_id = VGA_SWITCHEROO_DIS; 849 } 850 851 if (client_id == VGA_SWITCHEROO_UNKNOWN_ID) 852 goto out; 853 client = find_client_from_id(&vgasr_priv.clients, client_id); 854 if (!client) 855 goto out; 856 857 vgasr_priv.delayed_switch_active = false; 858 859 if (just_mux) { 860 mutex_lock(&vgasr_priv.mux_hw_lock); 861 ret = vgasr_priv.handler->switchto(client_id); 862 mutex_unlock(&vgasr_priv.mux_hw_lock); 863 goto out; 864 } 865 866 if (client->active) 867 goto out; 868 869 /* okay we want a switch - test if devices are willing to switch */ 870 can_switch = check_can_switch(); 871 872 if (can_switch == false && delay == false) 873 goto out; 874 875 if (can_switch) { 876 ret = vga_switchto_stage1(client); 877 if (ret) 878 pr_err("switching failed stage 1 %d\n", ret); 879 880 ret = vga_switchto_stage2(client); 881 if (ret) 882 pr_err("switching failed stage 2 %d\n", ret); 883 884 } else { 885 pr_info("setting delayed switch to client %d\n", client->id); 886 vgasr_priv.delayed_switch_active = true; 887 vgasr_priv.delayed_client_id = client_id; 888 889 ret = vga_switchto_stage1(client); 890 if (ret) 891 pr_err("delayed switching stage 1 failed %d\n", ret); 892 } 893 894out: 895 mutex_unlock(&vgasr_mutex); 896 return cnt; 897} 898 899static const struct file_operations vga_switcheroo_debugfs_fops = { 900 .owner = THIS_MODULE, 901 .open = vga_switcheroo_debugfs_open, 902 .write = vga_switcheroo_debugfs_write, 903 .read = seq_read, 904 .llseek = seq_lseek, 905 .release = single_release, 906}; 907 908static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv) 909{ 910 debugfs_remove_recursive(priv->debugfs_root); 911 priv->debugfs_root = NULL; 912} 913 914static void vga_switcheroo_debugfs_init(struct vgasr_priv *priv) 915{ 916 /* already initialised */ 917 if (priv->debugfs_root) 918 return; 919 920 priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL); 921 922 debugfs_create_file("switch", 0644, priv->debugfs_root, NULL, 923 &vga_switcheroo_debugfs_fops); 924} 925 926/** 927 * vga_switcheroo_process_delayed_switch() - helper for delayed switching 928 * 929 * Process a delayed switch if one is pending. DRM drivers should call this 930 * from their ->lastclose callback. 931 * 932 * Return: 0 on success. -EINVAL if no delayed switch is pending, if the client 933 * has unregistered in the meantime or if there are other clients blocking the 934 * switch. If the actual switch fails, an error is reported and 0 is returned. 935 */ 936int vga_switcheroo_process_delayed_switch(void) 937{ 938 struct vga_switcheroo_client *client; 939 int ret; 940 int err = -EINVAL; 941 942 mutex_lock(&vgasr_mutex); 943 if (!vgasr_priv.delayed_switch_active) 944 goto err; 945 946 pr_info("processing delayed switch to %d\n", 947 vgasr_priv.delayed_client_id); 948 949 client = find_client_from_id(&vgasr_priv.clients, 950 vgasr_priv.delayed_client_id); 951 if (!client || !check_can_switch()) 952 goto err; 953 954 ret = vga_switchto_stage2(client); 955 if (ret) 956 pr_err("delayed switching failed stage 2 %d\n", ret); 957 958 vgasr_priv.delayed_switch_active = false; 959 err = 0; 960err: 961 mutex_unlock(&vgasr_mutex); 962 return err; 963} 964EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch); 965 966/** 967 * DOC: Driver power control 968 * 969 * In this mode of use, the discrete GPU automatically powers up and down at 970 * the discretion of the driver's runtime pm. On muxed machines, the user may 971 * still influence the muxer state by way of the debugfs interface, however 972 * the ON and OFF commands become a no-op for the discrete GPU. 973 * 974 * This mode is the default on Nvidia HybridPower/Optimus and ATI PowerXpress. 975 * Specifying nouveau.runpm=0, radeon.runpm=0 or amdgpu.runpm=0 on the kernel 976 * command line disables it. 977 * 978 * After the GPU has been suspended, the handler needs to be called to cut 979 * power to the GPU. Likewise it needs to reinstate power before the GPU 980 * can resume. This is achieved by vga_switcheroo_init_domain_pm_ops(), 981 * which augments the GPU's suspend/resume functions by the requisite 982 * calls to the handler. 983 * 984 * When the audio device resumes, the GPU needs to be woken. This is achieved 985 * by a PCI quirk which calls device_link_add() to declare a dependency on the 986 * GPU. That way, the GPU is kept awake whenever and as long as the audio 987 * device is in use. 988 * 989 * On muxed machines, if the mux is initially switched to the discrete GPU, 990 * the user ends up with a black screen when the GPU powers down after boot. 991 * As a workaround, the mux is forced to the integrated GPU on runtime suspend, 992 * cf. https://bugs.freedesktop.org/show_bug.cgi?id=75917 993 */ 994 995static void vga_switcheroo_power_switch(struct pci_dev *pdev, 996 enum vga_switcheroo_state state) 997{ 998 struct vga_switcheroo_client *client; 999 1000 if (!vgasr_priv.handler->power_state) 1001 return; 1002 1003 client = find_client_from_pci(&vgasr_priv.clients, pdev); 1004 if (!client) 1005 return; 1006 1007 if (!client->driver_power_control) 1008 return; 1009 1010 vgasr_priv.handler->power_state(client->id, state); 1011} 1012 1013/* switcheroo power domain */ 1014static int vga_switcheroo_runtime_suspend(struct device *dev) 1015{ 1016 struct pci_dev *pdev = to_pci_dev(dev); 1017 int ret; 1018 1019 ret = dev->bus->pm->runtime_suspend(dev); 1020 if (ret) 1021 return ret; 1022 mutex_lock(&vgasr_mutex); 1023 if (vgasr_priv.handler->switchto) { 1024 mutex_lock(&vgasr_priv.mux_hw_lock); 1025 vgasr_priv.handler->switchto(VGA_SWITCHEROO_IGD); 1026 mutex_unlock(&vgasr_priv.mux_hw_lock); 1027 } 1028 pci_bus_set_current_state(pdev->bus, PCI_D3cold); 1029 vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_OFF); 1030 mutex_unlock(&vgasr_mutex); 1031 return 0; 1032} 1033 1034static int vga_switcheroo_runtime_resume(struct device *dev) 1035{ 1036 struct pci_dev *pdev = to_pci_dev(dev); 1037 1038 mutex_lock(&vgasr_mutex); 1039 vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_ON); 1040 mutex_unlock(&vgasr_mutex); 1041 pci_resume_bus(pdev->bus); 1042 return dev->bus->pm->runtime_resume(dev); 1043} 1044 1045/** 1046 * vga_switcheroo_init_domain_pm_ops() - helper for driver power control 1047 * @dev: vga client device 1048 * @domain: power domain 1049 * 1050 * Helper for GPUs whose power state is controlled by the driver's runtime pm. 1051 * After the GPU has been suspended, the handler needs to be called to cut 1052 * power to the GPU. Likewise it needs to reinstate power before the GPU 1053 * can resume. To this end, this helper augments the suspend/resume functions 1054 * by the requisite calls to the handler. It needs only be called on platforms 1055 * where the power switch is separate to the device being powered down. 1056 */ 1057int vga_switcheroo_init_domain_pm_ops(struct device *dev, 1058 struct dev_pm_domain *domain) 1059{ 1060 /* copy over all the bus versions */ 1061 if (dev->bus && dev->bus->pm) { 1062 domain->ops = *dev->bus->pm; 1063 domain->ops.runtime_suspend = vga_switcheroo_runtime_suspend; 1064 domain->ops.runtime_resume = vga_switcheroo_runtime_resume; 1065 1066 dev_pm_domain_set(dev, domain); 1067 return 0; 1068 } 1069 dev_pm_domain_set(dev, NULL); 1070 return -EINVAL; 1071} 1072EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_ops); 1073 1074void vga_switcheroo_fini_domain_pm_ops(struct device *dev) 1075{ 1076 dev_pm_domain_set(dev, NULL); 1077} 1078EXPORT_SYMBOL(vga_switcheroo_fini_domain_pm_ops); 1079