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/apple-gmux.h>
34 #include <linux/console.h>
35 #include <linux/debugfs.h>
38 #include <linux/module.h>
39 #include <linux/pci.h>
40 #include <linux/pm_domain.h>
41 #include <linux/pm_runtime.h>
42 #include <linux/seq_file.h>
43 #include <linux/uaccess.h>
44 #include <linux/vgaarb.h>
45 #include <linux/vga_switcheroo.h>
50 * vga_switcheroo is the Linux subsystem for laptop hybrid graphics.
51 * These come in two flavors:
53 * * muxed: Dual GPUs with a multiplexer chip to switch outputs between GPUs.
54 * * muxless: Dual GPUs but only one of them is connected to outputs.
55 * The other one is merely used to offload rendering, its results
56 * are copied over PCIe into the framebuffer. On Linux this is
57 * supported with DRI PRIME.
59 * Hybrid graphics started to appear in the late Naughties and were initially
60 * all muxed. Newer laptops moved to a muxless architecture for cost reasons.
61 * A notable exception is the MacBook Pro which continues to use a mux.
62 * Muxes come with varying capabilities: Some switch only the panel, others
63 * can also switch external displays. Some switch all display pins at once
64 * while others can switch just the DDC lines. (To allow EDID probing
65 * for the inactive GPU.) Also, muxes are often used to cut power to the
66 * discrete GPU while it is not used.
68 * DRM drivers register GPUs with vga_switcheroo, these are henceforth called
69 * clients. The mux is called the handler. Muxless machines also register a
70 * handler to control the power state of the discrete GPU, its ->switchto
71 * callback is a no-op for obvious reasons. The discrete GPU is often equipped
72 * with an HDA controller for the HDMI/DP audio signal, this will also
73 * register as a client so that vga_switcheroo can take care of the correct
74 * suspend/resume order when changing the discrete GPU's power state. In total
75 * there can thus be up to three clients: Two vga clients (GPUs) and one audio
76 * client (on the discrete GPU). The code is mostly prepared to support
77 * machines with more than two GPUs should they become available.
79 * The GPU to which the outputs are currently switched is called the
80 * active client in vga_switcheroo parlance. The GPU not in use is the
81 * inactive client. When the inactive client's DRM driver is loaded,
82 * it will be unable to probe the panel's EDID and hence depends on
83 * VBIOS to provide its display modes. If the VBIOS modes are bogus or
84 * if there is no VBIOS at all (which is common on the MacBook Pro),
85 * a client may alternatively request that the DDC lines are temporarily
86 * switched to it, provided that the handler supports this. Switching
87 * only the DDC lines and not the entire output avoids unnecessary
92 * struct vga_switcheroo_client - registered client
93 * @pdev: client pci device
94 * @fb_info: framebuffer to which console is remapped on switching
95 * @pwr_state: current power state if manual power control is used.
96 * For driver power control, call vga_switcheroo_pwr_state().
97 * @ops: client callbacks
98 * @id: client identifier. Determining the id requires the handler,
99 * so gpus are initially assigned VGA_SWITCHEROO_UNKNOWN_ID
100 * and later given their true id in vga_switcheroo_enable()
101 * @active: whether the outputs are currently switched to this client
102 * @driver_power_control: whether power state is controlled by the driver's
103 * runtime pm. If true, writing ON and OFF to the vga_switcheroo debugfs
104 * interface is a no-op so as not to interfere with runtime pm
106 * @vga_dev: pci device, indicate which GPU is bound to current audio client
108 * Registered client. A client can be either a GPU or an audio device on a GPU.
109 * For audio clients, the @fb_info and @active members are bogus. For GPU
110 * clients, the @vga_dev is bogus.
112 struct vga_switcheroo_client {
113 struct pci_dev *pdev;
114 struct fb_info *fb_info;
115 enum vga_switcheroo_state pwr_state;
116 const struct vga_switcheroo_client_ops *ops;
117 enum vga_switcheroo_client_id id;
119 bool driver_power_control;
120 struct list_head list;
121 struct pci_dev *vga_dev;
125 * protects access to struct vgasr_priv
127 static DEFINE_MUTEX(vgasr_mutex);
130 * struct vgasr_priv - vga_switcheroo private data
131 * @active: whether vga_switcheroo is enabled.
132 * Prerequisite is the registration of two GPUs and a handler
133 * @delayed_switch_active: whether a delayed switch is pending
134 * @delayed_client_id: client to which a delayed switch is pending
135 * @debugfs_root: directory for vga_switcheroo debugfs interface
136 * @switch_file: file 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
146 * vga_switcheroo private data. Currently only one vga_switcheroo instance
147 * per system is supported.
151 bool delayed_switch_active;
152 enum vga_switcheroo_client_id delayed_client_id;
154 struct dentry *debugfs_root;
155 struct dentry *switch_file;
157 int registered_clients;
158 struct list_head clients;
160 const struct vga_switcheroo_handler *handler;
161 enum vga_switcheroo_handler_flags_t handler_flags;
162 struct mutex mux_hw_lock;
166 #define ID_BIT_AUDIO 0x100
167 #define client_is_audio(c) ((c)->id & ID_BIT_AUDIO)
168 #define client_is_vga(c) (!client_is_audio(c))
169 #define client_id(c) ((c)->id & ~ID_BIT_AUDIO)
171 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
172 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
174 /* only one switcheroo per system */
175 static struct vgasr_priv vgasr_priv = {
176 .clients = LIST_HEAD_INIT(vgasr_priv.clients),
177 .mux_hw_lock = __MUTEX_INITIALIZER(vgasr_priv.mux_hw_lock),
180 static bool vga_switcheroo_ready(void)
182 /* we're ready if we get two clients + handler */
183 return !vgasr_priv.active &&
184 vgasr_priv.registered_clients == 2 && vgasr_priv.handler;
187 static void vga_switcheroo_enable(void)
190 struct vga_switcheroo_client *client;
192 /* call the handler to init */
193 if (vgasr_priv.handler->init)
194 vgasr_priv.handler->init();
196 list_for_each_entry(client, &vgasr_priv.clients, list) {
197 if (!client_is_vga(client) ||
198 client_id(client) != VGA_SWITCHEROO_UNKNOWN_ID)
201 ret = vgasr_priv.handler->get_client_id(client->pdev);
208 list_for_each_entry(client, &vgasr_priv.clients, list) {
209 if (!client_is_audio(client) ||
210 client_id(client) != VGA_SWITCHEROO_UNKNOWN_ID)
213 ret = vgasr_priv.handler->get_client_id(client->vga_dev);
217 client->id = ret | ID_BIT_AUDIO;
220 vga_switcheroo_debugfs_init(&vgasr_priv);
221 vgasr_priv.active = true;
225 * vga_switcheroo_register_handler() - register handler
226 * @handler: handler callbacks
227 * @handler_flags: handler flags
229 * Register handler. Enable vga_switcheroo if two vga clients have already
232 * Return: 0 on success, -EINVAL if a handler was already registered.
234 int vga_switcheroo_register_handler(
235 const struct vga_switcheroo_handler *handler,
236 enum vga_switcheroo_handler_flags_t handler_flags)
238 mutex_lock(&vgasr_mutex);
239 if (vgasr_priv.handler) {
240 mutex_unlock(&vgasr_mutex);
244 vgasr_priv.handler = handler;
245 vgasr_priv.handler_flags = handler_flags;
246 if (vga_switcheroo_ready()) {
247 pr_info("enabled\n");
248 vga_switcheroo_enable();
250 mutex_unlock(&vgasr_mutex);
253 EXPORT_SYMBOL(vga_switcheroo_register_handler);
256 * vga_switcheroo_unregister_handler() - unregister handler
258 * Unregister handler. Disable vga_switcheroo.
260 void vga_switcheroo_unregister_handler(void)
262 mutex_lock(&vgasr_mutex);
263 mutex_lock(&vgasr_priv.mux_hw_lock);
264 vgasr_priv.handler_flags = 0;
265 vgasr_priv.handler = NULL;
266 if (vgasr_priv.active) {
267 pr_info("disabled\n");
268 vga_switcheroo_debugfs_fini(&vgasr_priv);
269 vgasr_priv.active = false;
271 mutex_unlock(&vgasr_priv.mux_hw_lock);
272 mutex_unlock(&vgasr_mutex);
274 EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
277 * vga_switcheroo_handler_flags() - obtain handler flags
279 * Helper for clients to obtain the handler flags bitmask.
281 * Return: Handler flags. A value of 0 means that no handler is registered
282 * or that the handler has no special capabilities.
284 enum vga_switcheroo_handler_flags_t vga_switcheroo_handler_flags(void)
286 return vgasr_priv.handler_flags;
288 EXPORT_SYMBOL(vga_switcheroo_handler_flags);
290 static int register_client(struct pci_dev *pdev,
291 const struct vga_switcheroo_client_ops *ops,
292 enum vga_switcheroo_client_id id,
293 struct pci_dev *vga_dev,
295 bool driver_power_control)
297 struct vga_switcheroo_client *client;
299 client = kzalloc(sizeof(*client), GFP_KERNEL);
303 client->pwr_state = VGA_SWITCHEROO_ON;
307 client->active = active;
308 client->driver_power_control = driver_power_control;
309 client->vga_dev = vga_dev;
311 mutex_lock(&vgasr_mutex);
312 list_add_tail(&client->list, &vgasr_priv.clients);
313 if (client_is_vga(client))
314 vgasr_priv.registered_clients++;
316 if (vga_switcheroo_ready()) {
317 pr_info("enabled\n");
318 vga_switcheroo_enable();
320 mutex_unlock(&vgasr_mutex);
325 * vga_switcheroo_register_client - register vga client
326 * @pdev: client pci device
327 * @ops: client callbacks
328 * @driver_power_control: whether power state is controlled by the driver's
331 * Register vga client (GPU). Enable vga_switcheroo if another GPU and a
332 * handler have already registered. The power state of the client is assumed
333 * to be ON. Beforehand, vga_switcheroo_client_probe_defer() shall be called
334 * to ensure that all prerequisites are met.
336 * Return: 0 on success, -ENOMEM on memory allocation error.
338 int vga_switcheroo_register_client(struct pci_dev *pdev,
339 const struct vga_switcheroo_client_ops *ops,
340 bool driver_power_control)
342 return register_client(pdev, ops, VGA_SWITCHEROO_UNKNOWN_ID, NULL,
343 pdev == vga_default_device(),
344 driver_power_control);
346 EXPORT_SYMBOL(vga_switcheroo_register_client);
349 * vga_switcheroo_register_audio_client - register audio client
350 * @pdev: client pci device
351 * @ops: client callbacks
352 * @vga_dev: pci device which is bound to current audio client
354 * Register audio client (audio device on a GPU). The client is assumed
355 * to use runtime PM. Beforehand, vga_switcheroo_client_probe_defer()
356 * shall be called to ensure that all prerequisites are met.
358 * Return: 0 on success, -ENOMEM on memory allocation error, -EINVAL on getting
361 int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
362 const struct vga_switcheroo_client_ops *ops,
363 struct pci_dev *vga_dev)
365 enum vga_switcheroo_client_id id = VGA_SWITCHEROO_UNKNOWN_ID;
368 * if vga_switcheroo has enabled, that mean two GPU clients and also
369 * handler are registered. Get audio client id from bound GPU client
370 * id directly, otherwise, set it as VGA_SWITCHEROO_UNKNOWN_ID,
371 * it will set to correct id in later when vga_switcheroo_enable()
374 mutex_lock(&vgasr_mutex);
375 if (vgasr_priv.active) {
376 id = vgasr_priv.handler->get_client_id(vga_dev);
378 mutex_unlock(&vgasr_mutex);
382 mutex_unlock(&vgasr_mutex);
384 return register_client(pdev, ops, id | ID_BIT_AUDIO, vga_dev,
387 EXPORT_SYMBOL(vga_switcheroo_register_audio_client);
389 static struct vga_switcheroo_client *
390 find_client_from_pci(struct list_head *head, struct pci_dev *pdev)
392 struct vga_switcheroo_client *client;
394 list_for_each_entry(client, head, list)
395 if (client->pdev == pdev)
400 static struct vga_switcheroo_client *
401 find_client_from_id(struct list_head *head,
402 enum vga_switcheroo_client_id client_id)
404 struct vga_switcheroo_client *client;
406 list_for_each_entry(client, head, list)
407 if (client->id == client_id)
412 static struct vga_switcheroo_client *
413 find_active_client(struct list_head *head)
415 struct vga_switcheroo_client *client;
417 list_for_each_entry(client, head, list)
424 * vga_switcheroo_client_probe_defer() - whether to defer probing a given client
425 * @pdev: client pci device
427 * Determine whether any prerequisites are not fulfilled to probe a given
428 * client. Drivers shall invoke this early on in their ->probe callback
429 * and return %-EPROBE_DEFER if it evaluates to %true. Thou shalt not
430 * register the client ere thou hast called this.
432 * Return: %true if probing should be deferred, otherwise %false.
434 bool vga_switcheroo_client_probe_defer(struct pci_dev *pdev)
436 if ((pdev->class >> 16) == PCI_BASE_CLASS_DISPLAY) {
438 * apple-gmux is needed on pre-retina MacBook Pro
439 * to probe the panel if pdev is the inactive GPU.
441 if (apple_gmux_present() && pdev != vga_default_device() &&
442 !vgasr_priv.handler_flags)
448 EXPORT_SYMBOL(vga_switcheroo_client_probe_defer);
450 static enum vga_switcheroo_state
451 vga_switcheroo_pwr_state(struct vga_switcheroo_client *client)
453 if (client->driver_power_control)
454 if (pm_runtime_enabled(&client->pdev->dev) &&
455 pm_runtime_active(&client->pdev->dev))
456 return VGA_SWITCHEROO_ON;
458 return VGA_SWITCHEROO_OFF;
460 return client->pwr_state;
464 * vga_switcheroo_get_client_state() - obtain power state of a given client
465 * @pdev: client pci device
467 * Obtain power state of a given client as seen from vga_switcheroo.
468 * The function is only called from hda_intel.c.
470 * Return: Power state.
472 enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *pdev)
474 struct vga_switcheroo_client *client;
475 enum vga_switcheroo_state ret;
477 mutex_lock(&vgasr_mutex);
478 client = find_client_from_pci(&vgasr_priv.clients, pdev);
480 ret = VGA_SWITCHEROO_NOT_FOUND;
482 ret = vga_switcheroo_pwr_state(client);
483 mutex_unlock(&vgasr_mutex);
486 EXPORT_SYMBOL(vga_switcheroo_get_client_state);
489 * vga_switcheroo_unregister_client() - unregister client
490 * @pdev: client pci device
492 * Unregister client. Disable vga_switcheroo if this is a vga client (GPU).
494 void vga_switcheroo_unregister_client(struct pci_dev *pdev)
496 struct vga_switcheroo_client *client;
498 mutex_lock(&vgasr_mutex);
499 client = find_client_from_pci(&vgasr_priv.clients, pdev);
501 if (client_is_vga(client))
502 vgasr_priv.registered_clients--;
503 list_del(&client->list);
506 if (vgasr_priv.active && vgasr_priv.registered_clients < 2) {
507 pr_info("disabled\n");
508 vga_switcheroo_debugfs_fini(&vgasr_priv);
509 vgasr_priv.active = false;
511 mutex_unlock(&vgasr_mutex);
513 EXPORT_SYMBOL(vga_switcheroo_unregister_client);
516 * vga_switcheroo_client_fb_set() - set framebuffer of a given client
517 * @pdev: client pci device
520 * Set framebuffer of a given client. The console will be remapped to this
523 void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
524 struct fb_info *info)
526 struct vga_switcheroo_client *client;
528 mutex_lock(&vgasr_mutex);
529 client = find_client_from_pci(&vgasr_priv.clients, pdev);
531 client->fb_info = info;
532 mutex_unlock(&vgasr_mutex);
534 EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
537 * vga_switcheroo_lock_ddc() - temporarily switch DDC lines to a given client
538 * @pdev: client pci device
540 * Temporarily switch DDC lines to the client identified by @pdev
541 * (but leave the outputs otherwise switched to where they are).
542 * This allows the inactive client to probe EDID. The DDC lines must
543 * afterwards be switched back by calling vga_switcheroo_unlock_ddc(),
544 * even if this function returns an error.
546 * Return: Previous DDC owner on success or a negative int on error.
547 * Specifically, %-ENODEV if no handler has registered or if the handler
548 * does not support switching the DDC lines. Also, a negative value
549 * returned by the handler is propagated back to the caller.
550 * The return value has merely an informational purpose for any caller
551 * which might be interested in it. It is acceptable to ignore the return
552 * value and simply rely on the result of the subsequent EDID probe,
553 * which will be %NULL if DDC switching failed.
555 int vga_switcheroo_lock_ddc(struct pci_dev *pdev)
557 enum vga_switcheroo_client_id id;
559 mutex_lock(&vgasr_priv.mux_hw_lock);
560 if (!vgasr_priv.handler || !vgasr_priv.handler->switch_ddc) {
561 vgasr_priv.old_ddc_owner = -ENODEV;
565 id = vgasr_priv.handler->get_client_id(pdev);
566 vgasr_priv.old_ddc_owner = vgasr_priv.handler->switch_ddc(id);
567 return vgasr_priv.old_ddc_owner;
569 EXPORT_SYMBOL(vga_switcheroo_lock_ddc);
572 * vga_switcheroo_unlock_ddc() - switch DDC lines back to previous owner
573 * @pdev: client pci device
575 * Switch DDC lines back to the previous owner after calling
576 * vga_switcheroo_lock_ddc(). This must be called even if
577 * vga_switcheroo_lock_ddc() returned an error.
579 * Return: Previous DDC owner on success (i.e. the client identifier of @pdev)
580 * or a negative int on error.
581 * Specifically, %-ENODEV if no handler has registered or if the handler
582 * does not support switching the DDC lines. Also, a negative value
583 * returned by the handler is propagated back to the caller.
584 * Finally, invoking this function without calling vga_switcheroo_lock_ddc()
585 * first is not allowed and will result in %-EINVAL.
587 int vga_switcheroo_unlock_ddc(struct pci_dev *pdev)
589 enum vga_switcheroo_client_id id;
590 int ret = vgasr_priv.old_ddc_owner;
592 if (WARN_ON_ONCE(!mutex_is_locked(&vgasr_priv.mux_hw_lock)))
595 if (vgasr_priv.old_ddc_owner >= 0) {
596 id = vgasr_priv.handler->get_client_id(pdev);
597 if (vgasr_priv.old_ddc_owner != id)
598 ret = vgasr_priv.handler->switch_ddc(
599 vgasr_priv.old_ddc_owner);
601 mutex_unlock(&vgasr_priv.mux_hw_lock);
604 EXPORT_SYMBOL(vga_switcheroo_unlock_ddc);
607 * DOC: Manual switching and manual power control
609 * In this mode of use, the file /sys/kernel/debug/vgaswitcheroo/switch
610 * can be read to retrieve the current vga_switcheroo state and commands
611 * can be written to it to change the state. The file appears as soon as
612 * two GPU drivers and one handler have registered with vga_switcheroo.
613 * The following commands are understood:
615 * * OFF: Power off the device not in use.
616 * * ON: Power on the device not in use.
617 * * IGD: Switch to the integrated graphics device.
618 * Power on the integrated GPU if necessary, power off the discrete GPU.
619 * Prerequisite is that no user space processes (e.g. Xorg, alsactl)
620 * have opened device files of the GPUs or the audio client. If the
621 * switch fails, the user may invoke lsof(8) or fuser(1) on /dev/dri/
622 * and /dev/snd/controlC1 to identify processes blocking the switch.
623 * * DIS: Switch to the discrete graphics device.
624 * * DIGD: Delayed switch to the integrated graphics device.
625 * This will perform the switch once the last user space process has
626 * closed the device files of the GPUs and the audio client.
627 * * DDIS: Delayed switch to the discrete graphics device.
628 * * MIGD: Mux-only switch to the integrated graphics device.
629 * Does not remap console or change the power state of either gpu.
630 * If the integrated GPU is currently off, the screen will turn black.
631 * If it is on, the screen will show whatever happens to be in VRAM.
632 * Either way, the user has to blindly enter the command to switch back.
633 * * MDIS: Mux-only switch to the discrete graphics device.
635 * For GPUs whose power state is controlled by the driver's runtime pm,
636 * the ON and OFF commands are a no-op (see next section).
638 * For muxless machines, the IGD/DIS, DIGD/DDIS and MIGD/MDIS commands
639 * should not be used.
642 static int vga_switcheroo_show(struct seq_file *m, void *v)
644 struct vga_switcheroo_client *client;
647 mutex_lock(&vgasr_mutex);
648 list_for_each_entry(client, &vgasr_priv.clients, list) {
649 seq_printf(m, "%d:%s%s:%c:%s%s:%s\n", i,
650 client_id(client) == VGA_SWITCHEROO_DIS ? "DIS" :
652 client_is_vga(client) ? "" : "-Audio",
653 client->active ? '+' : ' ',
654 client->driver_power_control ? "Dyn" : "",
655 vga_switcheroo_pwr_state(client) ? "Pwr" : "Off",
656 pci_name(client->pdev));
659 mutex_unlock(&vgasr_mutex);
663 static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
665 return single_open(file, vga_switcheroo_show, NULL);
668 static int vga_switchon(struct vga_switcheroo_client *client)
670 if (client->driver_power_control)
672 if (vgasr_priv.handler->power_state)
673 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
674 /* call the driver callback to turn on device */
675 client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);
676 client->pwr_state = VGA_SWITCHEROO_ON;
680 static int vga_switchoff(struct vga_switcheroo_client *client)
682 if (client->driver_power_control)
684 /* call the driver callback to turn off device */
685 client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
686 if (vgasr_priv.handler->power_state)
687 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
688 client->pwr_state = VGA_SWITCHEROO_OFF;
692 static void set_audio_state(enum vga_switcheroo_client_id id,
693 enum vga_switcheroo_state state)
695 struct vga_switcheroo_client *client;
697 client = find_client_from_id(&vgasr_priv.clients, id | ID_BIT_AUDIO);
699 client->ops->set_gpu_state(client->pdev, state);
702 /* stage one happens before delay */
703 static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
705 struct vga_switcheroo_client *active;
707 active = find_active_client(&vgasr_priv.clients);
711 if (vga_switcheroo_pwr_state(new_client) == VGA_SWITCHEROO_OFF)
712 vga_switchon(new_client);
714 vga_set_default_device(new_client->pdev);
719 static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
722 struct vga_switcheroo_client *active;
724 active = find_active_client(&vgasr_priv.clients);
728 active->active = false;
730 /* let HDA controller autosuspend if GPU uses driver power control */
731 if (!active->driver_power_control)
732 set_audio_state(active->id, VGA_SWITCHEROO_OFF);
734 if (new_client->fb_info) {
735 struct fb_event event;
738 event.info = new_client->fb_info;
739 fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
743 mutex_lock(&vgasr_priv.mux_hw_lock);
744 ret = vgasr_priv.handler->switchto(new_client->id);
745 mutex_unlock(&vgasr_priv.mux_hw_lock);
749 if (new_client->ops->reprobe)
750 new_client->ops->reprobe(new_client->pdev);
752 if (vga_switcheroo_pwr_state(active) == VGA_SWITCHEROO_ON)
753 vga_switchoff(active);
755 /* let HDA controller autoresume if GPU uses driver power control */
756 if (!new_client->driver_power_control)
757 set_audio_state(new_client->id, VGA_SWITCHEROO_ON);
759 new_client->active = true;
763 static bool check_can_switch(void)
765 struct vga_switcheroo_client *client;
767 list_for_each_entry(client, &vgasr_priv.clients, list) {
768 if (!client->ops->can_switch(client->pdev)) {
769 pr_err("client %x refused switch\n", client->id);
777 vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
778 size_t cnt, loff_t *ppos)
782 bool delay = false, can_switch;
783 bool just_mux = false;
784 enum vga_switcheroo_client_id client_id = VGA_SWITCHEROO_UNKNOWN_ID;
785 struct vga_switcheroo_client *client = NULL;
790 if (copy_from_user(usercmd, ubuf, cnt))
793 mutex_lock(&vgasr_mutex);
795 if (!vgasr_priv.active) {
800 /* pwr off the device not in use */
801 if (strncmp(usercmd, "OFF", 3) == 0) {
802 list_for_each_entry(client, &vgasr_priv.clients, list) {
803 if (client->active || client_is_audio(client))
805 if (client->driver_power_control)
807 set_audio_state(client->id, VGA_SWITCHEROO_OFF);
808 if (client->pwr_state == VGA_SWITCHEROO_ON)
809 vga_switchoff(client);
813 /* pwr on the device not in use */
814 if (strncmp(usercmd, "ON", 2) == 0) {
815 list_for_each_entry(client, &vgasr_priv.clients, list) {
816 if (client->active || client_is_audio(client))
818 if (client->driver_power_control)
820 if (client->pwr_state == VGA_SWITCHEROO_OFF)
821 vga_switchon(client);
822 set_audio_state(client->id, VGA_SWITCHEROO_ON);
827 /* request a delayed switch - test can we switch now */
828 if (strncmp(usercmd, "DIGD", 4) == 0) {
829 client_id = VGA_SWITCHEROO_IGD;
833 if (strncmp(usercmd, "DDIS", 4) == 0) {
834 client_id = VGA_SWITCHEROO_DIS;
838 if (strncmp(usercmd, "IGD", 3) == 0)
839 client_id = VGA_SWITCHEROO_IGD;
841 if (strncmp(usercmd, "DIS", 3) == 0)
842 client_id = VGA_SWITCHEROO_DIS;
844 if (strncmp(usercmd, "MIGD", 4) == 0) {
846 client_id = VGA_SWITCHEROO_IGD;
848 if (strncmp(usercmd, "MDIS", 4) == 0) {
850 client_id = VGA_SWITCHEROO_DIS;
853 if (client_id == VGA_SWITCHEROO_UNKNOWN_ID)
855 client = find_client_from_id(&vgasr_priv.clients, client_id);
859 vgasr_priv.delayed_switch_active = false;
862 mutex_lock(&vgasr_priv.mux_hw_lock);
863 ret = vgasr_priv.handler->switchto(client_id);
864 mutex_unlock(&vgasr_priv.mux_hw_lock);
871 /* okay we want a switch - test if devices are willing to switch */
872 can_switch = check_can_switch();
874 if (can_switch == false && delay == false)
878 ret = vga_switchto_stage1(client);
880 pr_err("switching failed stage 1 %d\n", ret);
882 ret = vga_switchto_stage2(client);
884 pr_err("switching failed stage 2 %d\n", ret);
887 pr_info("setting delayed switch to client %d\n", client->id);
888 vgasr_priv.delayed_switch_active = true;
889 vgasr_priv.delayed_client_id = client_id;
891 ret = vga_switchto_stage1(client);
893 pr_err("delayed switching stage 1 failed %d\n", ret);
897 mutex_unlock(&vgasr_mutex);
901 static const struct file_operations vga_switcheroo_debugfs_fops = {
902 .owner = THIS_MODULE,
903 .open = vga_switcheroo_debugfs_open,
904 .write = vga_switcheroo_debugfs_write,
907 .release = single_release,
910 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
912 debugfs_remove(priv->switch_file);
913 priv->switch_file = NULL;
915 debugfs_remove(priv->debugfs_root);
916 priv->debugfs_root = NULL;
919 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
921 static const char mp[] = "/sys/kernel/debug";
923 /* already initialised */
924 if (priv->debugfs_root)
926 priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
928 if (!priv->debugfs_root) {
929 pr_err("Cannot create %s/vgaswitcheroo\n", mp);
933 priv->switch_file = debugfs_create_file("switch", 0644,
934 priv->debugfs_root, NULL,
935 &vga_switcheroo_debugfs_fops);
936 if (!priv->switch_file) {
937 pr_err("cannot create %s/vgaswitcheroo/switch\n", mp);
942 vga_switcheroo_debugfs_fini(priv);
947 * vga_switcheroo_process_delayed_switch() - helper for delayed switching
949 * Process a delayed switch if one is pending. DRM drivers should call this
950 * from their ->lastclose callback.
952 * Return: 0 on success. -EINVAL if no delayed switch is pending, if the client
953 * has unregistered in the meantime or if there are other clients blocking the
954 * switch. If the actual switch fails, an error is reported and 0 is returned.
956 int vga_switcheroo_process_delayed_switch(void)
958 struct vga_switcheroo_client *client;
962 mutex_lock(&vgasr_mutex);
963 if (!vgasr_priv.delayed_switch_active)
966 pr_info("processing delayed switch to %d\n",
967 vgasr_priv.delayed_client_id);
969 client = find_client_from_id(&vgasr_priv.clients,
970 vgasr_priv.delayed_client_id);
971 if (!client || !check_can_switch())
974 ret = vga_switchto_stage2(client);
976 pr_err("delayed switching failed stage 2 %d\n", ret);
978 vgasr_priv.delayed_switch_active = false;
981 mutex_unlock(&vgasr_mutex);
984 EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
987 * DOC: Driver power control
989 * In this mode of use, the discrete GPU automatically powers up and down at
990 * the discretion of the driver's runtime pm. On muxed machines, the user may
991 * still influence the muxer state by way of the debugfs interface, however
992 * the ON and OFF commands become a no-op for the discrete GPU.
994 * This mode is the default on Nvidia HybridPower/Optimus and ATI PowerXpress.
995 * Specifying nouveau.runpm=0, radeon.runpm=0 or amdgpu.runpm=0 on the kernel
996 * command line disables it.
998 * After the GPU has been suspended, the handler needs to be called to cut
999 * power to the GPU. Likewise it needs to reinstate power before the GPU
1000 * can resume. This is achieved by vga_switcheroo_init_domain_pm_ops(),
1001 * which augments the GPU's suspend/resume functions by the requisite
1002 * calls to the handler.
1004 * When the audio device resumes, the GPU needs to be woken. This is achieved
1005 * by a PCI quirk which calls device_link_add() to declare a dependency on the
1006 * GPU. That way, the GPU is kept awake whenever and as long as the audio
1009 * On muxed machines, if the mux is initially switched to the discrete GPU,
1010 * the user ends up with a black screen when the GPU powers down after boot.
1011 * As a workaround, the mux is forced to the integrated GPU on runtime suspend,
1012 * cf. https://bugs.freedesktop.org/show_bug.cgi?id=75917
1015 static void vga_switcheroo_power_switch(struct pci_dev *pdev,
1016 enum vga_switcheroo_state state)
1018 struct vga_switcheroo_client *client;
1020 if (!vgasr_priv.handler->power_state)
1023 client = find_client_from_pci(&vgasr_priv.clients, pdev);
1027 if (!client->driver_power_control)
1030 vgasr_priv.handler->power_state(client->id, state);
1033 /* switcheroo power domain */
1034 static int vga_switcheroo_runtime_suspend(struct device *dev)
1036 struct pci_dev *pdev = to_pci_dev(dev);
1039 ret = dev->bus->pm->runtime_suspend(dev);
1042 mutex_lock(&vgasr_mutex);
1043 if (vgasr_priv.handler->switchto) {
1044 mutex_lock(&vgasr_priv.mux_hw_lock);
1045 vgasr_priv.handler->switchto(VGA_SWITCHEROO_IGD);
1046 mutex_unlock(&vgasr_priv.mux_hw_lock);
1048 pci_bus_set_current_state(pdev->bus, PCI_D3cold);
1049 vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_OFF);
1050 mutex_unlock(&vgasr_mutex);
1054 static int vga_switcheroo_runtime_resume(struct device *dev)
1056 struct pci_dev *pdev = to_pci_dev(dev);
1059 mutex_lock(&vgasr_mutex);
1060 vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_ON);
1061 mutex_unlock(&vgasr_mutex);
1062 pci_wakeup_bus(pdev->bus);
1063 ret = dev->bus->pm->runtime_resume(dev);
1071 * vga_switcheroo_init_domain_pm_ops() - helper for driver power control
1072 * @dev: vga client device
1073 * @domain: power domain
1075 * Helper for GPUs whose power state is controlled by the driver's runtime pm.
1076 * After the GPU has been suspended, the handler needs to be called to cut
1077 * power to the GPU. Likewise it needs to reinstate power before the GPU
1078 * can resume. To this end, this helper augments the suspend/resume functions
1079 * by the requisite calls to the handler. It needs only be called on platforms
1080 * where the power switch is separate to the device being powered down.
1082 int vga_switcheroo_init_domain_pm_ops(struct device *dev,
1083 struct dev_pm_domain *domain)
1085 /* copy over all the bus versions */
1086 if (dev->bus && dev->bus->pm) {
1087 domain->ops = *dev->bus->pm;
1088 domain->ops.runtime_suspend = vga_switcheroo_runtime_suspend;
1089 domain->ops.runtime_resume = vga_switcheroo_runtime_resume;
1091 dev_pm_domain_set(dev, domain);
1094 dev_pm_domain_set(dev, NULL);
1097 EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_ops);
1099 void vga_switcheroo_fini_domain_pm_ops(struct device *dev)
1101 dev_pm_domain_set(dev, NULL);
1103 EXPORT_SYMBOL(vga_switcheroo_fini_domain_pm_ops);