1078 lines · c
1/*2 * vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs3 *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 a10 * copy of this software and associated documentation files (the "Software"),11 * to deal in the Software without restriction, including without limitation12 * the rights to use, copy, modify, merge, publish, distribute, sublicense,13 * and/or sell copies of the Software, and to permit persons to whom the14 * Software is furnished to do so, subject to the following conditions:15 *16 * The above copyright notice and this permission notice (including the next17 * paragraph) shall be included in all copies or substantial portions of the18 * Software.19 *20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL23 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING25 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER26 * DEALINGS27 * IN THE SOFTWARE.28 *29 */30 31#define pr_fmt(fmt) "vga_switcheroo: " fmt32 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: Overview50 *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 results57 * are copied over PCIe into the framebuffer. On Linux this is58 * supported with DRI PRIME.59 *60 * Hybrid graphics started to appear in the late Naughties and were initially61 * 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, others64 * can also switch external displays. Some switch all display pins at once65 * while others can switch just the DDC lines. (To allow EDID probing66 * for the inactive GPU.) Also, muxes are often used to cut power to the67 * discrete GPU while it is not used.68 *69 * DRM drivers register GPUs with vga_switcheroo, these are henceforth called70 * clients. The mux is called the handler. Muxless machines also register a71 * handler to control the power state of the discrete GPU, its ->switchto72 * callback is a no-op for obvious reasons. The discrete GPU is often equipped73 * with an HDA controller for the HDMI/DP audio signal, this will also74 * register as a client so that vga_switcheroo can take care of the correct75 * suspend/resume order when changing the discrete GPU's power state. In total76 * there can thus be up to three clients: Two vga clients (GPUs) and one audio77 * client (on the discrete GPU). The code is mostly prepared to support78 * machines with more than two GPUs should they become available.79 *80 * The GPU to which the outputs are currently switched is called the81 * active client in vga_switcheroo parlance. The GPU not in use is the82 * 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 on84 * VBIOS to provide its display modes. If the VBIOS modes are bogus or85 * 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 temporarily87 * switched to it, provided that the handler supports this. Switching88 * only the DDC lines and not the entire output avoids unnecessary89 * flickering.90 */91 92/**93 * struct vga_switcheroo_client - registered client94 * @pdev: client pci device95 * @fb_info: framebuffer to which console is remapped on switching96 * @pwr_state: current power state if manual power control is used.97 * For driver power control, call vga_switcheroo_pwr_state().98 * @ops: client callbacks99 * @id: client identifier. Determining the id requires the handler,100 * so gpus are initially assigned VGA_SWITCHEROO_UNKNOWN_ID101 * and later given their true id in vga_switcheroo_enable()102 * @active: whether the outputs are currently switched to this client103 * @driver_power_control: whether power state is controlled by the driver's104 * runtime pm. If true, writing ON and OFF to the vga_switcheroo debugfs105 * interface is a no-op so as not to interfere with runtime pm106 * @list: client list107 * @vga_dev: pci device, indicate which GPU is bound to current audio client108 *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 GPU111 * 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_priv127 */128static DEFINE_MUTEX(vgasr_mutex);129 130/**131 * struct vgasr_priv - vga_switcheroo private data132 * @active: whether vga_switcheroo is enabled.133 * Prerequisite is the registration of two GPUs and a handler134 * @delayed_switch_active: whether a delayed switch is pending135 * @delayed_client_id: client to which a delayed switch is pending136 * @debugfs_root: directory for vga_switcheroo debugfs interface137 * @registered_clients: number of registered GPUs138 * (counting only vga clients, not audio clients)139 * @clients: list of registered clients140 * @handler: registered handler141 * @handler_flags: flags of registered handler142 * @mux_hw_lock: protects mux state143 * (in particular while DDC lines are temporarily switched)144 * @old_ddc_owner: client to which DDC lines will be switched back on unlock145 *146 * vga_switcheroo private data. Currently only one vga_switcheroo instance147 * 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 0x100166#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 handler227 * @handler: handler callbacks228 * @handler_flags: handler flags229 *230 * Register handler. Enable vga_switcheroo if two vga clients have already231 * 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 handler258 *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 flags279 *280 * Helper for clients to obtain the handler flags bitmask.281 *282 * Return: Handler flags. A value of 0 means that no handler is registered283 * 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 client327 * @pdev: client pci device328 * @ops: client callbacks329 * @driver_power_control: whether power state is controlled by the driver's330 * runtime pm331 *332 * Register vga client (GPU). Enable vga_switcheroo if another GPU and a333 * handler have already registered. The power state of the client is assumed334 * to be ON. Beforehand, vga_switcheroo_client_probe_defer() shall be called335 * 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 client351 * @pdev: client pci device352 * @ops: client callbacks353 * @vga_dev: pci device which is bound to current audio client354 *355 * Register audio client (audio device on a GPU). The client is assumed356 * 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 getting360 * 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 also370 * handler are registered. Get audio client id from bound GPU client371 * 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 client429 * @pdev: client pci device430 *431 * Determine whether any prerequisites are not fulfilled to probe a given432 * client. Drivers shall invoke this early on in their ->probe callback433 * and return %-EPROBE_DEFER if it evaluates to %true. Thou shalt not434 * 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 Pro443 * 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_state455vga_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 else462 return VGA_SWITCHEROO_OFF;463 else464 return client->pwr_state;465}466 467/**468 * vga_switcheroo_get_client_state() - obtain power state of a given client469 * @pdev: client pci device470 *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 else486 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 client494 * @pdev: client pci device495 *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 client521 * @pdev: client pci device522 * @info: framebuffer523 *524 * Set framebuffer of a given client. The console will be remapped to this525 * 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 client542 * @pdev: client pci device543 *544 * Temporarily switch DDC lines to the client identified by @pdev545 * (but leave the outputs otherwise switched to where they are).546 * This allows the inactive client to probe EDID. The DDC lines must547 * 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 handler552 * does not support switching the DDC lines. Also, a negative value553 * returned by the handler is propagated back to the caller.554 * The return value has merely an informational purpose for any caller555 * which might be interested in it. It is acceptable to ignore the return556 * 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 owner577 * @pdev: client pci device578 *579 * Switch DDC lines back to the previous owner after calling580 * vga_switcheroo_lock_ddc(). This must be called even if581 * 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 handler586 * does not support switching the DDC lines. Also, a negative value587 * 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 control612 *613 * In this mode of use, the file /sys/kernel/debug/vgaswitcheroo/switch614 * can be read to retrieve the current vga_switcheroo state and commands615 * can be written to it to change the state. The file appears as soon as616 * 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 the625 * 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 has630 * 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 commands643 * 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_t775vga_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 switching928 *929 * Process a delayed switch if one is pending.930 *931 * Return: 0 on success. -EINVAL if no delayed switch is pending, if the client932 * has unregistered in the meantime or if there are other clients blocking the933 * switch. If the actual switch fails, an error is reported and 0 is returned.934 */935int vga_switcheroo_process_delayed_switch(void)936{937 struct vga_switcheroo_client *client;938 int ret;939 int err = -EINVAL;940 941 mutex_lock(&vgasr_mutex);942 if (!vgasr_priv.delayed_switch_active)943 goto err;944 945 pr_info("processing delayed switch to %d\n",946 vgasr_priv.delayed_client_id);947 948 client = find_client_from_id(&vgasr_priv.clients,949 vgasr_priv.delayed_client_id);950 if (!client || !check_can_switch())951 goto err;952 953 ret = vga_switchto_stage2(client);954 if (ret)955 pr_err("delayed switching failed stage 2 %d\n", ret);956 957 vgasr_priv.delayed_switch_active = false;958 err = 0;959err:960 mutex_unlock(&vgasr_mutex);961 return err;962}963EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);964 965/**966 * DOC: Driver power control967 *968 * In this mode of use, the discrete GPU automatically powers up and down at969 * the discretion of the driver's runtime pm. On muxed machines, the user may970 * still influence the muxer state by way of the debugfs interface, however971 * the ON and OFF commands become a no-op for the discrete GPU.972 *973 * This mode is the default on Nvidia HybridPower/Optimus and ATI PowerXpress.974 * Specifying nouveau.runpm=0, radeon.runpm=0 or amdgpu.runpm=0 on the kernel975 * command line disables it.976 *977 * After the GPU has been suspended, the handler needs to be called to cut978 * power to the GPU. Likewise it needs to reinstate power before the GPU979 * can resume. This is achieved by vga_switcheroo_init_domain_pm_ops(),980 * which augments the GPU's suspend/resume functions by the requisite981 * calls to the handler.982 *983 * When the audio device resumes, the GPU needs to be woken. This is achieved984 * by a PCI quirk which calls device_link_add() to declare a dependency on the985 * GPU. That way, the GPU is kept awake whenever and as long as the audio986 * device is in use.987 *988 * On muxed machines, if the mux is initially switched to the discrete GPU,989 * the user ends up with a black screen when the GPU powers down after boot.990 * As a workaround, the mux is forced to the integrated GPU on runtime suspend,991 * cf. https://bugs.freedesktop.org/show_bug.cgi?id=75917992 */993 994static void vga_switcheroo_power_switch(struct pci_dev *pdev,995 enum vga_switcheroo_state state)996{997 struct vga_switcheroo_client *client;998 999 if (!vgasr_priv.handler->power_state)1000 return;1001 1002 client = find_client_from_pci(&vgasr_priv.clients, pdev);1003 if (!client)1004 return;1005 1006 if (!client->driver_power_control)1007 return;1008 1009 vgasr_priv.handler->power_state(client->id, state);1010}1011 1012/* switcheroo power domain */1013static int vga_switcheroo_runtime_suspend(struct device *dev)1014{1015 struct pci_dev *pdev = to_pci_dev(dev);1016 int ret;1017 1018 ret = dev->bus->pm->runtime_suspend(dev);1019 if (ret)1020 return ret;1021 mutex_lock(&vgasr_mutex);1022 if (vgasr_priv.handler->switchto) {1023 mutex_lock(&vgasr_priv.mux_hw_lock);1024 vgasr_priv.handler->switchto(VGA_SWITCHEROO_IGD);1025 mutex_unlock(&vgasr_priv.mux_hw_lock);1026 }1027 pci_bus_set_current_state(pdev->bus, PCI_D3cold);1028 vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_OFF);1029 mutex_unlock(&vgasr_mutex);1030 return 0;1031}1032 1033static int vga_switcheroo_runtime_resume(struct device *dev)1034{1035 struct pci_dev *pdev = to_pci_dev(dev);1036 1037 mutex_lock(&vgasr_mutex);1038 vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_ON);1039 mutex_unlock(&vgasr_mutex);1040 pci_resume_bus(pdev->bus);1041 return dev->bus->pm->runtime_resume(dev);1042}1043 1044/**1045 * vga_switcheroo_init_domain_pm_ops() - helper for driver power control1046 * @dev: vga client device1047 * @domain: power domain1048 *1049 * Helper for GPUs whose power state is controlled by the driver's runtime pm.1050 * After the GPU has been suspended, the handler needs to be called to cut1051 * power to the GPU. Likewise it needs to reinstate power before the GPU1052 * can resume. To this end, this helper augments the suspend/resume functions1053 * by the requisite calls to the handler. It needs only be called on platforms1054 * where the power switch is separate to the device being powered down.1055 */1056int vga_switcheroo_init_domain_pm_ops(struct device *dev,1057 struct dev_pm_domain *domain)1058{1059 /* copy over all the bus versions */1060 if (dev->bus && dev->bus->pm) {1061 domain->ops = *dev->bus->pm;1062 domain->ops.runtime_suspend = vga_switcheroo_runtime_suspend;1063 domain->ops.runtime_resume = vga_switcheroo_runtime_resume;1064 1065 dev_pm_domain_set(dev, domain);1066 return 0;1067 }1068 dev_pm_domain_set(dev, NULL);1069 return -EINVAL;1070}1071EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_ops);1072 1073void vga_switcheroo_fini_domain_pm_ops(struct device *dev)1074{1075 dev_pm_domain_set(dev, NULL);1076}1077EXPORT_SYMBOL(vga_switcheroo_fini_domain_pm_ops);1078