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_domain.h>
40 #include <linux/pm_runtime.h>
41 #include <linux/seq_file.h>
42 #include <linux/uaccess.h>
43 #include <linux/vgaarb.h>
44 #include <linux/vga_switcheroo.h>
49 * vga_switcheroo is the Linux subsystem for laptop hybrid graphics.
50 * These come in two flavors:
52 * * muxed: Dual GPUs with a multiplexer chip to switch outputs between GPUs.
53 * * muxless: Dual GPUs but only one of them is connected to outputs.
54 * The other one is merely used to offload rendering, its results
55 * are copied over PCIe into the framebuffer. On Linux this is
56 * supported with DRI PRIME.
58 * Hybrid graphics started to appear in the late Naughties and were initially
59 * all muxed. Newer laptops moved to a muxless architecture for cost reasons.
60 * A notable exception is the MacBook Pro which continues to use a mux.
61 * Muxes come with varying capabilities: Some switch only the panel, others
62 * can also switch external displays. Some switch all display pins at once
63 * while others can switch just the DDC lines. (To allow EDID probing
64 * for the inactive GPU.) Also, muxes are often used to cut power to the
65 * discrete GPU while it is not used.
67 * DRM drivers register GPUs with vga_switcheroo, these are henceforth called
68 * clients. The mux is called the handler. Muxless machines also register a
69 * handler to control the power state of the discrete GPU, its ->switchto
70 * callback is a no-op for obvious reasons. The discrete GPU is often equipped
71 * with an HDA controller for the HDMI/DP audio signal, this will also
72 * register as a client so that vga_switcheroo can take care of the correct
73 * suspend/resume order when changing the discrete GPU's power state. In total
74 * there can thus be up to three clients: Two vga clients (GPUs) and one audio
75 * client (on the discrete GPU). The code is mostly prepared to support
76 * machines with more than two GPUs should they become available.
77 * The GPU to which the outputs are currently switched is called the
78 * active client in vga_switcheroo parlance. The GPU not in use is the
83 * struct vga_switcheroo_client - registered client
84 * @pdev: client pci device
85 * @fb_info: framebuffer to which console is remapped on switching
86 * @pwr_state: current power state
87 * @ops: client callbacks
88 * @id: client identifier. Determining the id requires the handler,
89 * so gpus are initially assigned VGA_SWITCHEROO_UNKNOWN_ID
90 * and later given their true id in vga_switcheroo_enable()
91 * @active: whether the outputs are currently switched to this client
92 * @driver_power_control: whether power state is controlled by the driver's
93 * runtime pm. If true, writing ON and OFF to the vga_switcheroo debugfs
94 * interface is a no-op so as not to interfere with runtime pm
97 * Registered client. A client can be either a GPU or an audio device on a GPU.
98 * For audio clients, the @fb_info, @active and @driver_power_control members
101 struct vga_switcheroo_client
{
102 struct pci_dev
*pdev
;
103 struct fb_info
*fb_info
;
104 enum vga_switcheroo_state pwr_state
;
105 const struct vga_switcheroo_client_ops
*ops
;
106 enum vga_switcheroo_client_id id
;
108 bool driver_power_control
;
109 struct list_head list
;
113 * protects access to struct vgasr_priv
115 static DEFINE_MUTEX(vgasr_mutex
);
118 * struct vgasr_priv - vga_switcheroo private data
119 * @active: whether vga_switcheroo is enabled.
120 * Prerequisite is the registration of two GPUs and a handler
121 * @delayed_switch_active: whether a delayed switch is pending
122 * @delayed_client_id: client to which a delayed switch is pending
123 * @debugfs_root: directory for vga_switcheroo debugfs interface
124 * @switch_file: file for vga_switcheroo debugfs interface
125 * @registered_clients: number of registered GPUs
126 * (counting only vga clients, not audio clients)
127 * @clients: list of registered clients
128 * @handler: registered handler
130 * vga_switcheroo private data. Currently only one vga_switcheroo instance
131 * per system is supported.
135 bool delayed_switch_active
;
136 enum vga_switcheroo_client_id delayed_client_id
;
138 struct dentry
*debugfs_root
;
139 struct dentry
*switch_file
;
141 int registered_clients
;
142 struct list_head clients
;
144 const struct vga_switcheroo_handler
*handler
;
147 #define ID_BIT_AUDIO 0x100
148 #define client_is_audio(c) ((c)->id & ID_BIT_AUDIO)
149 #define client_is_vga(c) ((c)->id == VGA_SWITCHEROO_UNKNOWN_ID || \
151 #define client_id(c) ((c)->id & ~ID_BIT_AUDIO)
153 static int vga_switcheroo_debugfs_init(struct vgasr_priv
*priv
);
154 static void vga_switcheroo_debugfs_fini(struct vgasr_priv
*priv
);
156 /* only one switcheroo per system */
157 static struct vgasr_priv vgasr_priv
= {
158 .clients
= LIST_HEAD_INIT(vgasr_priv
.clients
),
161 static bool vga_switcheroo_ready(void)
163 /* we're ready if we get two clients + handler */
164 return !vgasr_priv
.active
&&
165 vgasr_priv
.registered_clients
== 2 && vgasr_priv
.handler
;
168 static void vga_switcheroo_enable(void)
171 struct vga_switcheroo_client
*client
;
173 /* call the handler to init */
174 if (vgasr_priv
.handler
->init
)
175 vgasr_priv
.handler
->init();
177 list_for_each_entry(client
, &vgasr_priv
.clients
, list
) {
178 if (client
->id
!= VGA_SWITCHEROO_UNKNOWN_ID
)
180 ret
= vgasr_priv
.handler
->get_client_id(client
->pdev
);
186 vga_switcheroo_debugfs_init(&vgasr_priv
);
187 vgasr_priv
.active
= true;
191 * vga_switcheroo_register_handler() - register handler
192 * @handler: handler callbacks
194 * Register handler. Enable vga_switcheroo if two vga clients have already
197 * Return: 0 on success, -EINVAL if a handler was already registered.
199 int vga_switcheroo_register_handler(const struct vga_switcheroo_handler
*handler
)
201 mutex_lock(&vgasr_mutex
);
202 if (vgasr_priv
.handler
) {
203 mutex_unlock(&vgasr_mutex
);
207 vgasr_priv
.handler
= handler
;
208 if (vga_switcheroo_ready()) {
209 pr_info("enabled\n");
210 vga_switcheroo_enable();
212 mutex_unlock(&vgasr_mutex
);
215 EXPORT_SYMBOL(vga_switcheroo_register_handler
);
218 * vga_switcheroo_unregister_handler() - unregister handler
220 * Unregister handler. Disable vga_switcheroo.
222 void vga_switcheroo_unregister_handler(void)
224 mutex_lock(&vgasr_mutex
);
225 vgasr_priv
.handler
= NULL
;
226 if (vgasr_priv
.active
) {
227 pr_info("disabled\n");
228 vga_switcheroo_debugfs_fini(&vgasr_priv
);
229 vgasr_priv
.active
= false;
231 mutex_unlock(&vgasr_mutex
);
233 EXPORT_SYMBOL(vga_switcheroo_unregister_handler
);
235 static int register_client(struct pci_dev
*pdev
,
236 const struct vga_switcheroo_client_ops
*ops
,
237 enum vga_switcheroo_client_id id
, bool active
,
238 bool driver_power_control
)
240 struct vga_switcheroo_client
*client
;
242 client
= kzalloc(sizeof(*client
), GFP_KERNEL
);
246 client
->pwr_state
= VGA_SWITCHEROO_ON
;
250 client
->active
= active
;
251 client
->driver_power_control
= driver_power_control
;
253 mutex_lock(&vgasr_mutex
);
254 list_add_tail(&client
->list
, &vgasr_priv
.clients
);
255 if (client_is_vga(client
))
256 vgasr_priv
.registered_clients
++;
258 if (vga_switcheroo_ready()) {
259 pr_info("enabled\n");
260 vga_switcheroo_enable();
262 mutex_unlock(&vgasr_mutex
);
267 * vga_switcheroo_register_client - register vga client
268 * @pdev: client pci device
269 * @ops: client callbacks
270 * @driver_power_control: whether power state is controlled by the driver's
273 * Register vga client (GPU). Enable vga_switcheroo if another GPU and a
274 * handler have already registered. The power state of the client is assumed
277 * Return: 0 on success, -ENOMEM on memory allocation error.
279 int vga_switcheroo_register_client(struct pci_dev
*pdev
,
280 const struct vga_switcheroo_client_ops
*ops
,
281 bool driver_power_control
)
283 return register_client(pdev
, ops
, VGA_SWITCHEROO_UNKNOWN_ID
,
284 pdev
== vga_default_device(),
285 driver_power_control
);
287 EXPORT_SYMBOL(vga_switcheroo_register_client
);
290 * vga_switcheroo_register_audio_client - register audio client
291 * @pdev: client pci device
292 * @ops: client callbacks
293 * @id: client identifier
295 * Register audio client (audio device on a GPU). The power state of the
296 * client is assumed to be ON.
298 * Return: 0 on success, -ENOMEM on memory allocation error.
300 int vga_switcheroo_register_audio_client(struct pci_dev
*pdev
,
301 const struct vga_switcheroo_client_ops
*ops
,
302 enum vga_switcheroo_client_id id
)
304 return register_client(pdev
, ops
, id
| ID_BIT_AUDIO
, false, false);
306 EXPORT_SYMBOL(vga_switcheroo_register_audio_client
);
308 static struct vga_switcheroo_client
*
309 find_client_from_pci(struct list_head
*head
, struct pci_dev
*pdev
)
311 struct vga_switcheroo_client
*client
;
313 list_for_each_entry(client
, head
, list
)
314 if (client
->pdev
== pdev
)
319 static struct vga_switcheroo_client
*
320 find_client_from_id(struct list_head
*head
,
321 enum vga_switcheroo_client_id client_id
)
323 struct vga_switcheroo_client
*client
;
325 list_for_each_entry(client
, head
, list
)
326 if (client
->id
== client_id
)
331 static struct vga_switcheroo_client
*
332 find_active_client(struct list_head
*head
)
334 struct vga_switcheroo_client
*client
;
336 list_for_each_entry(client
, head
, list
)
343 * vga_switcheroo_get_client_state() - obtain power state of a given client
344 * @pdev: client pci device
346 * Obtain power state of a given client as seen from vga_switcheroo.
347 * The function is only called from hda_intel.c.
349 * Return: Power state.
351 enum vga_switcheroo_state
vga_switcheroo_get_client_state(struct pci_dev
*pdev
)
353 struct vga_switcheroo_client
*client
;
354 enum vga_switcheroo_state ret
;
356 mutex_lock(&vgasr_mutex
);
357 client
= find_client_from_pci(&vgasr_priv
.clients
, pdev
);
359 ret
= VGA_SWITCHEROO_NOT_FOUND
;
361 ret
= client
->pwr_state
;
362 mutex_unlock(&vgasr_mutex
);
365 EXPORT_SYMBOL(vga_switcheroo_get_client_state
);
368 * vga_switcheroo_unregister_client() - unregister client
369 * @pdev: client pci device
371 * Unregister client. Disable vga_switcheroo if this is a vga client (GPU).
373 void vga_switcheroo_unregister_client(struct pci_dev
*pdev
)
375 struct vga_switcheroo_client
*client
;
377 mutex_lock(&vgasr_mutex
);
378 client
= find_client_from_pci(&vgasr_priv
.clients
, pdev
);
380 if (client_is_vga(client
))
381 vgasr_priv
.registered_clients
--;
382 list_del(&client
->list
);
385 if (vgasr_priv
.active
&& vgasr_priv
.registered_clients
< 2) {
386 pr_info("disabled\n");
387 vga_switcheroo_debugfs_fini(&vgasr_priv
);
388 vgasr_priv
.active
= false;
390 mutex_unlock(&vgasr_mutex
);
392 EXPORT_SYMBOL(vga_switcheroo_unregister_client
);
395 * vga_switcheroo_client_fb_set() - set framebuffer of a given client
396 * @pdev: client pci device
399 * Set framebuffer of a given client. The console will be remapped to this
402 void vga_switcheroo_client_fb_set(struct pci_dev
*pdev
,
403 struct fb_info
*info
)
405 struct vga_switcheroo_client
*client
;
407 mutex_lock(&vgasr_mutex
);
408 client
= find_client_from_pci(&vgasr_priv
.clients
, pdev
);
410 client
->fb_info
= info
;
411 mutex_unlock(&vgasr_mutex
);
413 EXPORT_SYMBOL(vga_switcheroo_client_fb_set
);
416 * DOC: Manual switching and manual power control
418 * In this mode of use, the file /sys/kernel/debug/vgaswitcheroo/switch
419 * can be read to retrieve the current vga_switcheroo state and commands
420 * can be written to it to change the state. The file appears as soon as
421 * two GPU drivers and one handler have registered with vga_switcheroo.
422 * The following commands are understood:
424 * * OFF: Power off the device not in use.
425 * * ON: Power on the device not in use.
426 * * IGD: Switch to the integrated graphics device.
427 * Power on the integrated GPU if necessary, power off the discrete GPU.
428 * Prerequisite is that no user space processes (e.g. Xorg, alsactl)
429 * have opened device files of the GPUs or the audio client. If the
430 * switch fails, the user may invoke lsof(8) or fuser(1) on /dev/dri/
431 * and /dev/snd/controlC1 to identify processes blocking the switch.
432 * * DIS: Switch to the discrete graphics device.
433 * * DIGD: Delayed switch to the integrated graphics device.
434 * This will perform the switch once the last user space process has
435 * closed the device files of the GPUs and the audio client.
436 * * DDIS: Delayed switch to the discrete graphics device.
437 * * MIGD: Mux-only switch to the integrated graphics device.
438 * Does not remap console or change the power state of either gpu.
439 * If the integrated GPU is currently off, the screen will turn black.
440 * If it is on, the screen will show whatever happens to be in VRAM.
441 * Either way, the user has to blindly enter the command to switch back.
442 * * MDIS: Mux-only switch to the discrete graphics device.
444 * For GPUs whose power state is controlled by the driver's runtime pm,
445 * the ON and OFF commands are a no-op (see next section).
447 * For muxless machines, the IGD/DIS, DIGD/DDIS and MIGD/MDIS commands
448 * should not be used.
451 static int vga_switcheroo_show(struct seq_file
*m
, void *v
)
453 struct vga_switcheroo_client
*client
;
456 mutex_lock(&vgasr_mutex
);
457 list_for_each_entry(client
, &vgasr_priv
.clients
, list
) {
458 seq_printf(m
, "%d:%s%s:%c:%s%s:%s\n", i
,
459 client_id(client
) == VGA_SWITCHEROO_DIS
? "DIS" :
461 client_is_vga(client
) ? "" : "-Audio",
462 client
->active
? '+' : ' ',
463 client
->driver_power_control
? "Dyn" : "",
464 client
->pwr_state
? "Pwr" : "Off",
465 pci_name(client
->pdev
));
468 mutex_unlock(&vgasr_mutex
);
472 static int vga_switcheroo_debugfs_open(struct inode
*inode
, struct file
*file
)
474 return single_open(file
, vga_switcheroo_show
, NULL
);
477 static int vga_switchon(struct vga_switcheroo_client
*client
)
479 if (client
->driver_power_control
)
481 if (vgasr_priv
.handler
->power_state
)
482 vgasr_priv
.handler
->power_state(client
->id
, VGA_SWITCHEROO_ON
);
483 /* call the driver callback to turn on device */
484 client
->ops
->set_gpu_state(client
->pdev
, VGA_SWITCHEROO_ON
);
485 client
->pwr_state
= VGA_SWITCHEROO_ON
;
489 static int vga_switchoff(struct vga_switcheroo_client
*client
)
491 if (client
->driver_power_control
)
493 /* call the driver callback to turn off device */
494 client
->ops
->set_gpu_state(client
->pdev
, VGA_SWITCHEROO_OFF
);
495 if (vgasr_priv
.handler
->power_state
)
496 vgasr_priv
.handler
->power_state(client
->id
, VGA_SWITCHEROO_OFF
);
497 client
->pwr_state
= VGA_SWITCHEROO_OFF
;
501 static void set_audio_state(enum vga_switcheroo_client_id id
,
502 enum vga_switcheroo_state state
)
504 struct vga_switcheroo_client
*client
;
506 client
= find_client_from_id(&vgasr_priv
.clients
, id
| ID_BIT_AUDIO
);
507 if (client
&& client
->pwr_state
!= state
) {
508 client
->ops
->set_gpu_state(client
->pdev
, state
);
509 client
->pwr_state
= state
;
513 /* stage one happens before delay */
514 static int vga_switchto_stage1(struct vga_switcheroo_client
*new_client
)
516 struct vga_switcheroo_client
*active
;
518 active
= find_active_client(&vgasr_priv
.clients
);
522 if (new_client
->pwr_state
== VGA_SWITCHEROO_OFF
)
523 vga_switchon(new_client
);
525 vga_set_default_device(new_client
->pdev
);
530 static int vga_switchto_stage2(struct vga_switcheroo_client
*new_client
)
533 struct vga_switcheroo_client
*active
;
535 active
= find_active_client(&vgasr_priv
.clients
);
539 active
->active
= false;
541 set_audio_state(active
->id
, VGA_SWITCHEROO_OFF
);
543 if (new_client
->fb_info
) {
544 struct fb_event event
;
547 event
.info
= new_client
->fb_info
;
548 fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE
, &event
);
552 ret
= vgasr_priv
.handler
->switchto(new_client
->id
);
556 if (new_client
->ops
->reprobe
)
557 new_client
->ops
->reprobe(new_client
->pdev
);
559 if (active
->pwr_state
== VGA_SWITCHEROO_ON
)
560 vga_switchoff(active
);
562 set_audio_state(new_client
->id
, VGA_SWITCHEROO_ON
);
564 new_client
->active
= true;
568 static bool check_can_switch(void)
570 struct vga_switcheroo_client
*client
;
572 list_for_each_entry(client
, &vgasr_priv
.clients
, list
) {
573 if (!client
->ops
->can_switch(client
->pdev
)) {
574 pr_err("client %x refused switch\n", client
->id
);
582 vga_switcheroo_debugfs_write(struct file
*filp
, const char __user
*ubuf
,
583 size_t cnt
, loff_t
*ppos
)
587 bool delay
= false, can_switch
;
588 bool just_mux
= false;
589 enum vga_switcheroo_client_id client_id
= VGA_SWITCHEROO_UNKNOWN_ID
;
590 struct vga_switcheroo_client
*client
= NULL
;
595 if (copy_from_user(usercmd
, ubuf
, cnt
))
598 mutex_lock(&vgasr_mutex
);
600 if (!vgasr_priv
.active
) {
605 /* pwr off the device not in use */
606 if (strncmp(usercmd
, "OFF", 3) == 0) {
607 list_for_each_entry(client
, &vgasr_priv
.clients
, list
) {
608 if (client
->active
|| client_is_audio(client
))
610 if (client
->driver_power_control
)
612 set_audio_state(client
->id
, VGA_SWITCHEROO_OFF
);
613 if (client
->pwr_state
== VGA_SWITCHEROO_ON
)
614 vga_switchoff(client
);
618 /* pwr on the device not in use */
619 if (strncmp(usercmd
, "ON", 2) == 0) {
620 list_for_each_entry(client
, &vgasr_priv
.clients
, list
) {
621 if (client
->active
|| client_is_audio(client
))
623 if (client
->driver_power_control
)
625 if (client
->pwr_state
== VGA_SWITCHEROO_OFF
)
626 vga_switchon(client
);
627 set_audio_state(client
->id
, VGA_SWITCHEROO_ON
);
632 /* request a delayed switch - test can we switch now */
633 if (strncmp(usercmd
, "DIGD", 4) == 0) {
634 client_id
= VGA_SWITCHEROO_IGD
;
638 if (strncmp(usercmd
, "DDIS", 4) == 0) {
639 client_id
= VGA_SWITCHEROO_DIS
;
643 if (strncmp(usercmd
, "IGD", 3) == 0)
644 client_id
= VGA_SWITCHEROO_IGD
;
646 if (strncmp(usercmd
, "DIS", 3) == 0)
647 client_id
= VGA_SWITCHEROO_DIS
;
649 if (strncmp(usercmd
, "MIGD", 4) == 0) {
651 client_id
= VGA_SWITCHEROO_IGD
;
653 if (strncmp(usercmd
, "MDIS", 4) == 0) {
655 client_id
= VGA_SWITCHEROO_DIS
;
658 if (client_id
== VGA_SWITCHEROO_UNKNOWN_ID
)
660 client
= find_client_from_id(&vgasr_priv
.clients
, client_id
);
664 vgasr_priv
.delayed_switch_active
= false;
667 ret
= vgasr_priv
.handler
->switchto(client_id
);
674 /* okay we want a switch - test if devices are willing to switch */
675 can_switch
= check_can_switch();
677 if (can_switch
== false && delay
== false)
681 ret
= vga_switchto_stage1(client
);
683 pr_err("switching failed stage 1 %d\n", ret
);
685 ret
= vga_switchto_stage2(client
);
687 pr_err("switching failed stage 2 %d\n", ret
);
690 pr_info("setting delayed switch to client %d\n", client
->id
);
691 vgasr_priv
.delayed_switch_active
= true;
692 vgasr_priv
.delayed_client_id
= client_id
;
694 ret
= vga_switchto_stage1(client
);
696 pr_err("delayed switching stage 1 failed %d\n", ret
);
700 mutex_unlock(&vgasr_mutex
);
704 static const struct file_operations vga_switcheroo_debugfs_fops
= {
705 .owner
= THIS_MODULE
,
706 .open
= vga_switcheroo_debugfs_open
,
707 .write
= vga_switcheroo_debugfs_write
,
710 .release
= single_release
,
713 static void vga_switcheroo_debugfs_fini(struct vgasr_priv
*priv
)
715 debugfs_remove(priv
->switch_file
);
716 priv
->switch_file
= NULL
;
718 debugfs_remove(priv
->debugfs_root
);
719 priv
->debugfs_root
= NULL
;
722 static int vga_switcheroo_debugfs_init(struct vgasr_priv
*priv
)
724 static const char mp
[] = "/sys/kernel/debug";
726 /* already initialised */
727 if (priv
->debugfs_root
)
729 priv
->debugfs_root
= debugfs_create_dir("vgaswitcheroo", NULL
);
731 if (!priv
->debugfs_root
) {
732 pr_err("Cannot create %s/vgaswitcheroo\n", mp
);
736 priv
->switch_file
= debugfs_create_file("switch", 0644,
737 priv
->debugfs_root
, NULL
,
738 &vga_switcheroo_debugfs_fops
);
739 if (!priv
->switch_file
) {
740 pr_err("cannot create %s/vgaswitcheroo/switch\n", mp
);
745 vga_switcheroo_debugfs_fini(priv
);
750 * vga_switcheroo_process_delayed_switch() - helper for delayed switching
752 * Process a delayed switch if one is pending. DRM drivers should call this
753 * from their ->lastclose callback.
755 * Return: 0 on success. -EINVAL if no delayed switch is pending, if the client
756 * has unregistered in the meantime or if there are other clients blocking the
757 * switch. If the actual switch fails, an error is reported and 0 is returned.
759 int vga_switcheroo_process_delayed_switch(void)
761 struct vga_switcheroo_client
*client
;
765 mutex_lock(&vgasr_mutex
);
766 if (!vgasr_priv
.delayed_switch_active
)
769 pr_info("processing delayed switch to %d\n",
770 vgasr_priv
.delayed_client_id
);
772 client
= find_client_from_id(&vgasr_priv
.clients
,
773 vgasr_priv
.delayed_client_id
);
774 if (!client
|| !check_can_switch())
777 ret
= vga_switchto_stage2(client
);
779 pr_err("delayed switching failed stage 2 %d\n", ret
);
781 vgasr_priv
.delayed_switch_active
= false;
784 mutex_unlock(&vgasr_mutex
);
787 EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch
);
790 * DOC: Driver power control
792 * In this mode of use, the discrete GPU automatically powers up and down at
793 * the discretion of the driver's runtime pm. On muxed machines, the user may
794 * still influence the muxer state by way of the debugfs interface, however
795 * the ON and OFF commands become a no-op for the discrete GPU.
797 * This mode is the default on Nvidia HybridPower/Optimus and ATI PowerXpress.
798 * Specifying nouveau.runpm=0, radeon.runpm=0 or amdgpu.runpm=0 on the kernel
799 * command line disables it.
801 * When the driver decides to power up or down, it notifies vga_switcheroo
802 * thereof so that it can (a) power the audio device on the GPU up or down,
803 * and (b) update its internal power state representation for the device.
804 * This is achieved by vga_switcheroo_set_dynamic_switch().
806 * After the GPU has been suspended, the handler needs to be called to cut
807 * power to the GPU. Likewise it needs to reinstate power before the GPU
808 * can resume. This is achieved by vga_switcheroo_init_domain_pm_ops(),
809 * which augments the GPU's suspend/resume functions by the requisite
810 * calls to the handler.
812 * When the audio device resumes, the GPU needs to be woken. This is achieved
813 * by vga_switcheroo_init_domain_pm_optimus_hdmi_audio(), which augments the
814 * audio device's resume function.
816 * On muxed machines, if the mux is initially switched to the discrete GPU,
817 * the user ends up with a black screen when the GPU powers down after boot.
818 * As a workaround, the mux is forced to the integrated GPU on runtime suspend,
819 * cf. https://bugs.freedesktop.org/show_bug.cgi?id=75917
822 static void vga_switcheroo_power_switch(struct pci_dev
*pdev
,
823 enum vga_switcheroo_state state
)
825 struct vga_switcheroo_client
*client
;
827 if (!vgasr_priv
.handler
->power_state
)
830 client
= find_client_from_pci(&vgasr_priv
.clients
, pdev
);
834 if (!client
->driver_power_control
)
837 vgasr_priv
.handler
->power_state(client
->id
, state
);
841 * vga_switcheroo_set_dynamic_switch() - helper for driver power control
842 * @pdev: client pci device
843 * @dynamic: new power state
845 * Helper for GPUs whose power state is controlled by the driver's runtime pm.
846 * When the driver decides to power up or down, it notifies vga_switcheroo
847 * thereof using this helper so that it can (a) power the audio device on
848 * the GPU up or down, and (b) update its internal power state representation
851 void vga_switcheroo_set_dynamic_switch(struct pci_dev
*pdev
,
852 enum vga_switcheroo_state dynamic
)
854 struct vga_switcheroo_client
*client
;
856 mutex_lock(&vgasr_mutex
);
857 client
= find_client_from_pci(&vgasr_priv
.clients
, pdev
);
858 if (!client
|| !client
->driver_power_control
) {
859 mutex_unlock(&vgasr_mutex
);
863 client
->pwr_state
= dynamic
;
864 set_audio_state(client
->id
, dynamic
);
865 mutex_unlock(&vgasr_mutex
);
867 EXPORT_SYMBOL(vga_switcheroo_set_dynamic_switch
);
869 /* switcheroo power domain */
870 static int vga_switcheroo_runtime_suspend(struct device
*dev
)
872 struct pci_dev
*pdev
= to_pci_dev(dev
);
875 ret
= dev
->bus
->pm
->runtime_suspend(dev
);
878 mutex_lock(&vgasr_mutex
);
879 if (vgasr_priv
.handler
->switchto
)
880 vgasr_priv
.handler
->switchto(VGA_SWITCHEROO_IGD
);
881 vga_switcheroo_power_switch(pdev
, VGA_SWITCHEROO_OFF
);
882 mutex_unlock(&vgasr_mutex
);
886 static int vga_switcheroo_runtime_resume(struct device
*dev
)
888 struct pci_dev
*pdev
= to_pci_dev(dev
);
891 mutex_lock(&vgasr_mutex
);
892 vga_switcheroo_power_switch(pdev
, VGA_SWITCHEROO_ON
);
893 mutex_unlock(&vgasr_mutex
);
894 ret
= dev
->bus
->pm
->runtime_resume(dev
);
902 * vga_switcheroo_init_domain_pm_ops() - helper for driver power control
903 * @dev: vga client device
904 * @domain: power domain
906 * Helper for GPUs whose power state is controlled by the driver's runtime pm.
907 * After the GPU has been suspended, the handler needs to be called to cut
908 * power to the GPU. Likewise it needs to reinstate power before the GPU
909 * can resume. To this end, this helper augments the suspend/resume functions
910 * by the requisite calls to the handler. It needs only be called on platforms
911 * where the power switch is separate to the device being powered down.
913 int vga_switcheroo_init_domain_pm_ops(struct device
*dev
,
914 struct dev_pm_domain
*domain
)
916 /* copy over all the bus versions */
917 if (dev
->bus
&& dev
->bus
->pm
) {
918 domain
->ops
= *dev
->bus
->pm
;
919 domain
->ops
.runtime_suspend
= vga_switcheroo_runtime_suspend
;
920 domain
->ops
.runtime_resume
= vga_switcheroo_runtime_resume
;
922 dev_pm_domain_set(dev
, domain
);
925 dev_pm_domain_set(dev
, NULL
);
928 EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_ops
);
930 void vga_switcheroo_fini_domain_pm_ops(struct device
*dev
)
932 dev_pm_domain_set(dev
, NULL
);
934 EXPORT_SYMBOL(vga_switcheroo_fini_domain_pm_ops
);
936 static int vga_switcheroo_runtime_resume_hdmi_audio(struct device
*dev
)
938 struct pci_dev
*pdev
= to_pci_dev(dev
);
939 struct vga_switcheroo_client
*client
;
940 struct device
*video_dev
= NULL
;
943 /* we need to check if we have to switch back on the video
944 device so the audio device can come back */
945 mutex_lock(&vgasr_mutex
);
946 list_for_each_entry(client
, &vgasr_priv
.clients
, list
) {
947 if (PCI_SLOT(client
->pdev
->devfn
) == PCI_SLOT(pdev
->devfn
) &&
948 client_is_vga(client
)) {
949 video_dev
= &client
->pdev
->dev
;
953 mutex_unlock(&vgasr_mutex
);
956 ret
= pm_runtime_get_sync(video_dev
);
960 ret
= dev
->bus
->pm
->runtime_resume(dev
);
962 /* put the reference for the gpu */
964 pm_runtime_mark_last_busy(video_dev
);
965 pm_runtime_put_autosuspend(video_dev
);
971 * vga_switcheroo_init_domain_pm_optimus_hdmi_audio() - helper for driver
973 * @dev: audio client device
974 * @domain: power domain
976 * Helper for GPUs whose power state is controlled by the driver's runtime pm.
977 * When the audio device resumes, the GPU needs to be woken. This helper
978 * augments the audio device's resume function to do that.
980 * Return: 0 on success, -EINVAL if no power management operations are
981 * defined for this device.
984 vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device
*dev
,
985 struct dev_pm_domain
*domain
)
987 /* copy over all the bus versions */
988 if (dev
->bus
&& dev
->bus
->pm
) {
989 domain
->ops
= *dev
->bus
->pm
;
990 domain
->ops
.runtime_resume
=
991 vga_switcheroo_runtime_resume_hdmi_audio
;
993 dev_pm_domain_set(dev
, domain
);
996 dev_pm_domain_set(dev
, NULL
);
999 EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_optimus_hdmi_audio
);