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
);