2 * vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs
4 * Copyright (c) 2010 Red Hat Inc.
5 * Author : Dave Airlie <airlied@redhat.com>
7 * Copyright (c) 2015 Lukas Wunner <lukas@wunner.de>
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:
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
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
31 #define pr_fmt(fmt) "vga_switcheroo: " fmt
33 #include <linux/console.h>
34 #include <linux/debugfs.h>
37 #include <linux/module.h>
38 #include <linux/pci.h>
39 #include <linux/pm_runtime.h>
40 #include <linux/seq_file.h>
41 #include <linux/uaccess.h>
42 #include <linux/vgaarb.h>
43 #include <linux/vga_switcheroo.h>
48 * vga_switcheroo is the Linux subsystem for laptop hybrid graphics.
49 * These come in two flavors:
51 * * muxed: Dual GPUs with a multiplexer chip to switch outputs between GPUs.
52 * * muxless: Dual GPUs but only one of them is connected to outputs.
53 * The other one is merely used to offload rendering, its results
54 * are copied over PCIe into the framebuffer. On Linux this is
55 * supported with DRI PRIME.
57 * Hybrid graphics started to appear in the late Naughties and were initially
58 * all muxed. Newer laptops moved to a muxless architecture for cost reasons.
59 * A notable exception is the MacBook Pro which continues to use a mux.
60 * Muxes come with varying capabilities: Some switch only the panel, others
61 * can also switch external displays. Some switch all display pins at once
62 * while others can switch just the DDC lines. (To allow EDID probing
63 * for the inactive GPU.) Also, muxes are often used to cut power to the
64 * discrete GPU while it is not used.
66 * DRM drivers register GPUs with vga_switcheroo, these are heretoforth called
67 * clients. The mux is called the handler. Muxless machines also register a
68 * handler to control the power state of the discrete GPU, its ->switchto
69 * callback is a no-op for obvious reasons. The discrete GPU is often equipped
70 * with an HDA controller for the HDMI/DP audio signal, this will also
71 * register as a client so that vga_switcheroo can take care of the correct
72 * suspend/resume order when changing the discrete GPU's power state. In total
73 * there can thus be up to three clients: Two vga clients (GPUs) and one audio
74 * client (on the discrete GPU). The code is mostly prepared to support
75 * machines with more than two GPUs should they become available.
76 * The GPU to which the outputs are currently switched is called the
77 * active client in vga_switcheroo parlance. The GPU not in use is the
82 * struct vga_switcheroo_client - registered client
83 * @pdev: client pci device
84 * @fb_info: framebuffer to which console is remapped on switching
85 * @pwr_state: current power state
86 * @ops: client callbacks
87 * @id: client identifier. Determining the id requires the handler,
88 * so gpus are initially assigned VGA_SWITCHEROO_UNKNOWN_ID
89 * and later given their true id in vga_switcheroo_enable()
90 * @active: whether the outputs are currently switched to this client
91 * @driver_power_control: whether power state is controlled by the driver's
92 * runtime pm. If true, writing ON and OFF to the vga_switcheroo debugfs
93 * interface is a no-op so as not to interfere with runtime pm
96 * Registered client. A client can be either a GPU or an audio device on a GPU.
97 * For audio clients, the @fb_info, @active and @driver_power_control members
100 struct vga_switcheroo_client {
101 struct pci_dev *pdev;
102 struct fb_info *fb_info;
103 enum vga_switcheroo_state pwr_state;
104 const struct vga_switcheroo_client_ops *ops;
105 enum vga_switcheroo_client_id id;
107 bool driver_power_control;
108 struct list_head list;
112 * protects access to struct vgasr_priv
114 static DEFINE_MUTEX(vgasr_mutex);
117 * struct vgasr_priv - vga_switcheroo private data
118 * @active: whether vga_switcheroo is enabled.
119 * Prerequisite is the registration of two GPUs and a handler
120 * @delayed_switch_active: whether a delayed switch is pending
121 * @delayed_client_id: client to which a delayed switch is pending
122 * @debugfs_root: directory for vga_switcheroo debugfs interface
123 * @switch_file: file for vga_switcheroo debugfs interface
124 * @registered_clients: number of registered GPUs
125 * (counting only vga clients, not audio clients)
126 * @clients: list of registered clients
127 * @handler: registered handler
129 * vga_switcheroo private data. Currently only one vga_switcheroo instance
130 * per system is supported.
134 bool delayed_switch_active;
135 enum vga_switcheroo_client_id delayed_client_id;
137 struct dentry *debugfs_root;
138 struct dentry *switch_file;
140 int registered_clients;
141 struct list_head clients;
143 const struct vga_switcheroo_handler *handler;
146 #define ID_BIT_AUDIO 0x100
147 #define client_is_audio(c) ((c)->id & ID_BIT_AUDIO)
148 #define client_is_vga(c) ((c)->id == VGA_SWITCHEROO_UNKNOWN_ID || \
150 #define client_id(c) ((c)->id & ~ID_BIT_AUDIO)
152 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
153 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
155 /* only one switcheroo per system */
156 static struct vgasr_priv vgasr_priv = {
157 .clients = LIST_HEAD_INIT(vgasr_priv.clients),
160 static bool vga_switcheroo_ready(void)
162 /* we're ready if we get two clients + handler */
163 return !vgasr_priv.active &&
164 vgasr_priv.registered_clients == 2 && vgasr_priv.handler;
167 static void vga_switcheroo_enable(void)
170 struct vga_switcheroo_client *client;
172 /* call the handler to init */
173 if (vgasr_priv.handler->init)
174 vgasr_priv.handler->init();
176 list_for_each_entry(client, &vgasr_priv.clients, list) {
177 if (client->id != VGA_SWITCHEROO_UNKNOWN_ID)
179 ret = vgasr_priv.handler->get_client_id(client->pdev);
185 vga_switcheroo_debugfs_init(&vgasr_priv);
186 vgasr_priv.active = true;
190 * vga_switcheroo_register_handler() - register handler
191 * @handler: handler callbacks
193 * Register handler. Enable vga_switcheroo if two vga clients have already
196 * Return: 0 on success, -EINVAL if a handler was already registered.
198 int vga_switcheroo_register_handler(const struct vga_switcheroo_handler *handler)
200 mutex_lock(&vgasr_mutex);
201 if (vgasr_priv.handler) {
202 mutex_unlock(&vgasr_mutex);
206 vgasr_priv.handler = handler;
207 if (vga_switcheroo_ready()) {
208 pr_info("enabled\n");
209 vga_switcheroo_enable();
211 mutex_unlock(&vgasr_mutex);
214 EXPORT_SYMBOL(vga_switcheroo_register_handler);
217 * vga_switcheroo_unregister_handler() - unregister handler
219 * Unregister handler. Disable vga_switcheroo.
221 void vga_switcheroo_unregister_handler(void)
223 mutex_lock(&vgasr_mutex);
224 vgasr_priv.handler = NULL;
225 if (vgasr_priv.active) {
226 pr_info("disabled\n");
227 vga_switcheroo_debugfs_fini(&vgasr_priv);
228 vgasr_priv.active = false;
230 mutex_unlock(&vgasr_mutex);
232 EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
234 static int register_client(struct pci_dev *pdev,
235 const struct vga_switcheroo_client_ops *ops,
236 enum vga_switcheroo_client_id id, bool active,
237 bool driver_power_control)
239 struct vga_switcheroo_client *client;
241 client = kzalloc(sizeof(*client), GFP_KERNEL);
245 client->pwr_state = VGA_SWITCHEROO_ON;
249 client->active = active;
250 client->driver_power_control = driver_power_control;
252 mutex_lock(&vgasr_mutex);
253 list_add_tail(&client->list, &vgasr_priv.clients);
254 if (client_is_vga(client))
255 vgasr_priv.registered_clients++;
257 if (vga_switcheroo_ready()) {
258 pr_info("enabled\n");
259 vga_switcheroo_enable();
261 mutex_unlock(&vgasr_mutex);
266 * vga_switcheroo_register_client - register vga client
267 * @pdev: client pci device
268 * @ops: client callbacks
269 * @driver_power_control: whether power state is controlled by the driver's
272 * Register vga client (GPU). Enable vga_switcheroo if another GPU and a
273 * handler have already registered. The power state of the client is assumed
276 * Return: 0 on success, -ENOMEM on memory allocation error.
278 int vga_switcheroo_register_client(struct pci_dev *pdev,
279 const struct vga_switcheroo_client_ops *ops,
280 bool driver_power_control)
282 return register_client(pdev, ops, VGA_SWITCHEROO_UNKNOWN_ID,
283 pdev == vga_default_device(),
284 driver_power_control);
286 EXPORT_SYMBOL(vga_switcheroo_register_client);
289 * vga_switcheroo_register_audio_client - register audio client
290 * @pdev: client pci device
291 * @ops: client callbacks
292 * @id: client identifier
294 * Register audio client (audio device on a GPU). The power state of the
295 * client is assumed to be ON.
297 * Return: 0 on success, -ENOMEM on memory allocation error.
299 int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
300 const struct vga_switcheroo_client_ops *ops,
301 enum vga_switcheroo_client_id id)
303 return register_client(pdev, ops, id | ID_BIT_AUDIO, false, false);
305 EXPORT_SYMBOL(vga_switcheroo_register_audio_client);
307 static struct vga_switcheroo_client *
308 find_client_from_pci(struct list_head *head, struct pci_dev *pdev)
310 struct vga_switcheroo_client *client;
312 list_for_each_entry(client, head, list)
313 if (client->pdev == pdev)
318 static struct vga_switcheroo_client *
319 find_client_from_id(struct list_head *head,
320 enum vga_switcheroo_client_id client_id)
322 struct vga_switcheroo_client *client;
324 list_for_each_entry(client, head, list)
325 if (client->id == client_id)
330 static struct vga_switcheroo_client *
331 find_active_client(struct list_head *head)
333 struct vga_switcheroo_client *client;
335 list_for_each_entry(client, head, list)
342 * vga_switcheroo_get_client_state() - obtain power state of a given client
343 * @pdev: client pci device
345 * Obtain power state of a given client as seen from vga_switcheroo.
346 * The function is only called from hda_intel.c.
348 * Return: Power state.
350 enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *pdev)
352 struct vga_switcheroo_client *client;
353 enum vga_switcheroo_state ret;
355 mutex_lock(&vgasr_mutex);
356 client = find_client_from_pci(&vgasr_priv.clients, pdev);
358 ret = VGA_SWITCHEROO_NOT_FOUND;
360 ret = client->pwr_state;
361 mutex_unlock(&vgasr_mutex);
364 EXPORT_SYMBOL(vga_switcheroo_get_client_state);
367 * vga_switcheroo_unregister_client() - unregister client
368 * @pdev: client pci device
370 * Unregister client. Disable vga_switcheroo if this is a vga client (GPU).
372 void vga_switcheroo_unregister_client(struct pci_dev *pdev)
374 struct vga_switcheroo_client *client;
376 mutex_lock(&vgasr_mutex);
377 client = find_client_from_pci(&vgasr_priv.clients, pdev);
379 if (client_is_vga(client))
380 vgasr_priv.registered_clients--;
381 list_del(&client->list);
384 if (vgasr_priv.active && vgasr_priv.registered_clients < 2) {
385 pr_info("disabled\n");
386 vga_switcheroo_debugfs_fini(&vgasr_priv);
387 vgasr_priv.active = false;
389 mutex_unlock(&vgasr_mutex);
391 EXPORT_SYMBOL(vga_switcheroo_unregister_client);
394 * vga_switcheroo_client_fb_set() - set framebuffer of a given client
395 * @pdev: client pci device
398 * Set framebuffer of a given client. The console will be remapped to this
401 void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
402 struct fb_info *info)
404 struct vga_switcheroo_client *client;
406 mutex_lock(&vgasr_mutex);
407 client = find_client_from_pci(&vgasr_priv.clients, pdev);
409 client->fb_info = info;
410 mutex_unlock(&vgasr_mutex);
412 EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
415 * DOC: Manual switching and manual power control
417 * In this mode of use, the file /sys/kernel/debug/vgaswitcheroo/switch
418 * can be read to retrieve the current vga_switcheroo state and commands
419 * can be written to it to change the state. The file appears as soon as
420 * two GPU drivers and one handler have registered with vga_switcheroo.
421 * The following commands are understood:
423 * * OFF: Power off the device not in use.
424 * * ON: Power on the device not in use.
425 * * IGD: Switch to the integrated graphics device.
426 * Power on the integrated GPU if necessary, power off the discrete GPU.
427 * Prerequisite is that no user space processes (e.g. Xorg, alsactl)
428 * have opened device files of the GPUs or the audio client. If the
429 * switch fails, the user may invoke lsof(8) or fuser(1) on /dev/dri/
430 * and /dev/snd/controlC1 to identify processes blocking the switch.
431 * * DIS: Switch to the discrete graphics device.
432 * * DIGD: Delayed switch to the integrated graphics device.
433 * This will perform the switch once the last user space process has
434 * closed the device files of the GPUs and the audio client.
435 * * DDIS: Delayed switch to the discrete graphics device.
436 * * MIGD: Mux-only switch to the integrated graphics device.
437 * Does not remap console or change the power state of either gpu.
438 * If the integrated GPU is currently off, the screen will turn black.
439 * If it is on, the screen will show whatever happens to be in VRAM.
440 * Either way, the user has to blindly enter the command to switch back.
441 * * MDIS: Mux-only switch to the discrete graphics device.
443 * For GPUs whose power state is controlled by the driver's runtime pm,
444 * the ON and OFF commands are a no-op (see next section).
446 * For muxless machines, the IGD/DIS, DIGD/DDIS and MIGD/MDIS commands
447 * should not be used.
450 static int vga_switcheroo_show(struct seq_file *m, void *v)
452 struct vga_switcheroo_client *client;
455 mutex_lock(&vgasr_mutex);
456 list_for_each_entry(client, &vgasr_priv.clients, list) {
457 seq_printf(m, "%d:%s%s:%c:%s%s:%s\n", i,
458 client_id(client) == VGA_SWITCHEROO_DIS ? "DIS" :
460 client_is_vga(client) ? "" : "-Audio",
461 client->active ? '+' : ' ',
462 client->driver_power_control ? "Dyn" : "",
463 client->pwr_state ? "Pwr" : "Off",
464 pci_name(client->pdev));
467 mutex_unlock(&vgasr_mutex);
471 static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
473 return single_open(file, vga_switcheroo_show, NULL);
476 static int vga_switchon(struct vga_switcheroo_client *client)
478 if (client->driver_power_control)
480 if (vgasr_priv.handler->power_state)
481 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
482 /* call the driver callback to turn on device */
483 client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);
484 client->pwr_state = VGA_SWITCHEROO_ON;
488 static int vga_switchoff(struct vga_switcheroo_client *client)
490 if (client->driver_power_control)
492 /* call the driver callback to turn off device */
493 client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
494 if (vgasr_priv.handler->power_state)
495 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
496 client->pwr_state = VGA_SWITCHEROO_OFF;
500 static void set_audio_state(enum vga_switcheroo_client_id id,
501 enum vga_switcheroo_state state)
503 struct vga_switcheroo_client *client;
505 client = find_client_from_id(&vgasr_priv.clients, id | ID_BIT_AUDIO);
506 if (client && client->pwr_state != state) {
507 client->ops->set_gpu_state(client->pdev, state);
508 client->pwr_state = state;
512 /* stage one happens before delay */
513 static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
515 struct vga_switcheroo_client *active;
517 active = find_active_client(&vgasr_priv.clients);
521 if (new_client->pwr_state == VGA_SWITCHEROO_OFF)
522 vga_switchon(new_client);
524 vga_set_default_device(new_client->pdev);
529 static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
532 struct vga_switcheroo_client *active;
534 active = find_active_client(&vgasr_priv.clients);
538 active->active = false;
540 set_audio_state(active->id, VGA_SWITCHEROO_OFF);
542 if (new_client->fb_info) {
543 struct fb_event event;
546 event.info = new_client->fb_info;
547 fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
551 ret = vgasr_priv.handler->switchto(new_client->id);
555 if (new_client->ops->reprobe)
556 new_client->ops->reprobe(new_client->pdev);
558 if (active->pwr_state == VGA_SWITCHEROO_ON)
559 vga_switchoff(active);
561 set_audio_state(new_client->id, VGA_SWITCHEROO_ON);
563 new_client->active = true;
567 static bool check_can_switch(void)
569 struct vga_switcheroo_client *client;
571 list_for_each_entry(client, &vgasr_priv.clients, list) {
572 if (!client->ops->can_switch(client->pdev)) {
573 pr_err("client %x refused switch\n", client->id);
581 vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
582 size_t cnt, loff_t *ppos)
586 bool delay = false, can_switch;
587 bool just_mux = false;
588 enum vga_switcheroo_client_id client_id = VGA_SWITCHEROO_UNKNOWN_ID;
589 struct vga_switcheroo_client *client = NULL;
594 if (copy_from_user(usercmd, ubuf, cnt))
597 mutex_lock(&vgasr_mutex);
599 if (!vgasr_priv.active) {
604 /* pwr off the device not in use */
605 if (strncmp(usercmd, "OFF", 3) == 0) {
606 list_for_each_entry(client, &vgasr_priv.clients, list) {
607 if (client->active || client_is_audio(client))
609 if (client->driver_power_control)
611 set_audio_state(client->id, VGA_SWITCHEROO_OFF);
612 if (client->pwr_state == VGA_SWITCHEROO_ON)
613 vga_switchoff(client);
617 /* pwr on the device not in use */
618 if (strncmp(usercmd, "ON", 2) == 0) {
619 list_for_each_entry(client, &vgasr_priv.clients, list) {
620 if (client->active || client_is_audio(client))
622 if (client->driver_power_control)
624 if (client->pwr_state == VGA_SWITCHEROO_OFF)
625 vga_switchon(client);
626 set_audio_state(client->id, VGA_SWITCHEROO_ON);
631 /* request a delayed switch - test can we switch now */
632 if (strncmp(usercmd, "DIGD", 4) == 0) {
633 client_id = VGA_SWITCHEROO_IGD;
637 if (strncmp(usercmd, "DDIS", 4) == 0) {
638 client_id = VGA_SWITCHEROO_DIS;
642 if (strncmp(usercmd, "IGD", 3) == 0)
643 client_id = VGA_SWITCHEROO_IGD;
645 if (strncmp(usercmd, "DIS", 3) == 0)
646 client_id = VGA_SWITCHEROO_DIS;
648 if (strncmp(usercmd, "MIGD", 4) == 0) {
650 client_id = VGA_SWITCHEROO_IGD;
652 if (strncmp(usercmd, "MDIS", 4) == 0) {
654 client_id = VGA_SWITCHEROO_DIS;
657 if (client_id == VGA_SWITCHEROO_UNKNOWN_ID)
659 client = find_client_from_id(&vgasr_priv.clients, client_id);
663 vgasr_priv.delayed_switch_active = false;
666 ret = vgasr_priv.handler->switchto(client_id);
673 /* okay we want a switch - test if devices are willing to switch */
674 can_switch = check_can_switch();
676 if (can_switch == false && delay == false)
680 ret = vga_switchto_stage1(client);
682 pr_err("switching failed stage 1 %d\n", ret);
684 ret = vga_switchto_stage2(client);
686 pr_err("switching failed stage 2 %d\n", ret);
689 pr_info("setting delayed switch to client %d\n", client->id);
690 vgasr_priv.delayed_switch_active = true;
691 vgasr_priv.delayed_client_id = client_id;
693 ret = vga_switchto_stage1(client);
695 pr_err("delayed switching stage 1 failed %d\n", ret);
699 mutex_unlock(&vgasr_mutex);
703 static const struct file_operations vga_switcheroo_debugfs_fops = {
704 .owner = THIS_MODULE,
705 .open = vga_switcheroo_debugfs_open,
706 .write = vga_switcheroo_debugfs_write,
709 .release = single_release,
712 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
714 debugfs_remove(priv->switch_file);
715 priv->switch_file = NULL;
717 debugfs_remove(priv->debugfs_root);
718 priv->debugfs_root = NULL;
721 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
723 static const char mp[] = "/sys/kernel/debug";
725 /* already initialised */
726 if (priv->debugfs_root)
728 priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
730 if (!priv->debugfs_root) {
731 pr_err("Cannot create %s/vgaswitcheroo\n", mp);
735 priv->switch_file = debugfs_create_file("switch", 0644,
736 priv->debugfs_root, NULL,
737 &vga_switcheroo_debugfs_fops);
738 if (!priv->switch_file) {
739 pr_err("cannot create %s/vgaswitcheroo/switch\n", mp);
744 vga_switcheroo_debugfs_fini(priv);
749 * vga_switcheroo_process_delayed_switch() - helper for delayed switching
751 * Process a delayed switch if one is pending. DRM drivers should call this
752 * from their ->lastclose callback.
754 * Return: 0 on success. -EINVAL if no delayed switch is pending, if the client
755 * has unregistered in the meantime or if there are other clients blocking the
756 * switch. If the actual switch fails, an error is reported and 0 is returned.
758 int vga_switcheroo_process_delayed_switch(void)
760 struct vga_switcheroo_client *client;
764 mutex_lock(&vgasr_mutex);
765 if (!vgasr_priv.delayed_switch_active)
768 pr_info("processing delayed switch to %d\n",
769 vgasr_priv.delayed_client_id);
771 client = find_client_from_id(&vgasr_priv.clients,
772 vgasr_priv.delayed_client_id);
773 if (!client || !check_can_switch())
776 ret = vga_switchto_stage2(client);
778 pr_err("delayed switching failed stage 2 %d\n", ret);
780 vgasr_priv.delayed_switch_active = false;
783 mutex_unlock(&vgasr_mutex);
786 EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
789 * DOC: Driver power control
791 * In this mode of use, the discrete GPU automatically powers up and down at
792 * the discretion of the driver's runtime pm. On muxed machines, the user may
793 * still influence the muxer state by way of the debugfs interface, however
794 * the ON and OFF commands become a no-op for the discrete GPU.
796 * This mode is the default on Nvidia HybridPower/Optimus and ATI PowerXpress.
797 * Specifying nouveau.runpm=0, radeon.runpm=0 or amdgpu.runpm=0 on the kernel
798 * command line disables it.
800 * When the driver decides to power up or down, it notifies vga_switcheroo
801 * thereof so that it can (a) power the audio device on the GPU up or down,
802 * and (b) update its internal power state representation for the device.
803 * This is achieved by vga_switcheroo_set_dynamic_switch().
805 * After the GPU has been suspended, the handler needs to be called to cut
806 * power to the GPU. Likewise it needs to reinstate power before the GPU
807 * can resume. This is achieved by vga_switcheroo_init_domain_pm_ops(),
808 * which augments the GPU's suspend/resume functions by the requisite
809 * calls to the handler.
811 * When the audio device resumes, the GPU needs to be woken. This is achieved
812 * by vga_switcheroo_init_domain_pm_optimus_hdmi_audio(), which augments the
813 * audio device's resume function.
815 * On muxed machines, if the mux is initially switched to the discrete GPU,
816 * the user ends up with a black screen when the GPU powers down after boot.
817 * As a workaround, the mux is forced to the integrated GPU on runtime suspend,
818 * cf. https://bugs.freedesktop.org/show_bug.cgi?id=75917
821 static void vga_switcheroo_power_switch(struct pci_dev *pdev,
822 enum vga_switcheroo_state state)
824 struct vga_switcheroo_client *client;
826 if (!vgasr_priv.handler->power_state)
829 client = find_client_from_pci(&vgasr_priv.clients, pdev);
833 if (!client->driver_power_control)
836 vgasr_priv.handler->power_state(client->id, state);
840 * vga_switcheroo_set_dynamic_switch() - helper for driver power control
841 * @pdev: client pci device
842 * @dynamic: new power state
844 * Helper for GPUs whose power state is controlled by the driver's runtime pm.
845 * When the driver decides to power up or down, it notifies vga_switcheroo
846 * thereof using this helper so that it can (a) power the audio device on
847 * the GPU up or down, and (b) update its internal power state representation
850 void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev,
851 enum vga_switcheroo_state dynamic)
853 struct vga_switcheroo_client *client;
855 mutex_lock(&vgasr_mutex);
856 client = find_client_from_pci(&vgasr_priv.clients, pdev);
857 if (!client || !client->driver_power_control) {
858 mutex_unlock(&vgasr_mutex);
862 client->pwr_state = dynamic;
863 set_audio_state(client->id, dynamic);
864 mutex_unlock(&vgasr_mutex);
866 EXPORT_SYMBOL(vga_switcheroo_set_dynamic_switch);
868 /* switcheroo power domain */
869 static int vga_switcheroo_runtime_suspend(struct device *dev)
871 struct pci_dev *pdev = to_pci_dev(dev);
874 ret = dev->bus->pm->runtime_suspend(dev);
877 mutex_lock(&vgasr_mutex);
878 if (vgasr_priv.handler->switchto)
879 vgasr_priv.handler->switchto(VGA_SWITCHEROO_IGD);
880 vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_OFF);
881 mutex_unlock(&vgasr_mutex);
885 static int vga_switcheroo_runtime_resume(struct device *dev)
887 struct pci_dev *pdev = to_pci_dev(dev);
890 mutex_lock(&vgasr_mutex);
891 vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_ON);
892 mutex_unlock(&vgasr_mutex);
893 ret = dev->bus->pm->runtime_resume(dev);
901 * vga_switcheroo_init_domain_pm_ops() - helper for driver power control
902 * @dev: vga client device
903 * @domain: power domain
905 * Helper for GPUs whose power state is controlled by the driver's runtime pm.
906 * After the GPU has been suspended, the handler needs to be called to cut
907 * power to the GPU. Likewise it needs to reinstate power before the GPU
908 * can resume. To this end, this helper augments the suspend/resume functions
909 * by the requisite calls to the handler. It needs only be called on platforms
910 * where the power switch is separate to the device being powered down.
912 int vga_switcheroo_init_domain_pm_ops(struct device *dev,
913 struct dev_pm_domain *domain)
915 /* copy over all the bus versions */
916 if (dev->bus && dev->bus->pm) {
917 domain->ops = *dev->bus->pm;
918 domain->ops.runtime_suspend = vga_switcheroo_runtime_suspend;
919 domain->ops.runtime_resume = vga_switcheroo_runtime_resume;
921 dev->pm_domain = domain;
924 dev->pm_domain = NULL;
927 EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_ops);
929 void vga_switcheroo_fini_domain_pm_ops(struct device *dev)
931 dev->pm_domain = NULL;
933 EXPORT_SYMBOL(vga_switcheroo_fini_domain_pm_ops);
935 static int vga_switcheroo_runtime_resume_hdmi_audio(struct device *dev)
937 struct pci_dev *pdev = to_pci_dev(dev);
938 struct vga_switcheroo_client *client;
939 struct device *video_dev = NULL;
942 /* we need to check if we have to switch back on the video
943 device so the audio device can come back */
944 mutex_lock(&vgasr_mutex);
945 list_for_each_entry(client, &vgasr_priv.clients, list) {
946 if (PCI_SLOT(client->pdev->devfn) == PCI_SLOT(pdev->devfn) &&
947 client_is_vga(client)) {
948 video_dev = &client->pdev->dev;
952 mutex_unlock(&vgasr_mutex);
955 ret = pm_runtime_get_sync(video_dev);
959 ret = dev->bus->pm->runtime_resume(dev);
961 /* put the reference for the gpu */
963 pm_runtime_mark_last_busy(video_dev);
964 pm_runtime_put_autosuspend(video_dev);
970 * vga_switcheroo_init_domain_pm_optimus_hdmi_audio() - helper for driver
972 * @dev: audio client device
973 * @domain: power domain
975 * Helper for GPUs whose power state is controlled by the driver's runtime pm.
976 * When the audio device resumes, the GPU needs to be woken. This helper
977 * augments the audio device's resume function to do that.
979 * Return: 0 on success, -EINVAL if no power management operations are
980 * defined for this device.
983 vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev,
984 struct dev_pm_domain *domain)
986 /* copy over all the bus versions */
987 if (dev->bus && dev->bus->pm) {
988 domain->ops = *dev->bus->pm;
989 domain->ops.runtime_resume =
990 vga_switcheroo_runtime_resume_hdmi_audio;
992 dev->pm_domain = domain;
995 dev->pm_domain = NULL;
998 EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_optimus_hdmi_audio);