2  * vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs
33 #include <linux/apple-gmux.h>
66  * for the inactive GPU.) Also, muxes are often used to cut power to the
67  * discrete GPU while it is not used.
71  * handler to control the power state of the discrete GPU, its ->switchto
72  * callback is a no-op for obvious reasons. The discrete GPU is often equipped
75  * suspend/resume order when changing the discrete GPU's power state. In total
77  * client (on the discrete GPU). The code is mostly prepared to support
80  * The GPU to which the outputs are currently switched is called the
81  * active client in vga_switcheroo parlance. The GPU not in use is the
93  * struct vga_switcheroo_client - registered client
99  * @id: client identifier. Determining the id requires the handler,
101  *	and later given their true id in vga_switcheroo_enable()
105  *	interface is a no-op so as not to interfere with runtime pm
107  * @vga_dev: pci device, indicate which GPU is bound to current audio client
109  * Registered client. A client can be either a GPU or an audio device on a GPU.
110  * For audio clients, the @fb_info and @active members are bogus. For GPU
118 	enum vga_switcheroo_client_id id;  member
131  * struct vgasr_priv - vga_switcheroo private data
166 #define client_is_audio(c)		((c)->id & ID_BIT_AUDIO)
168 #define client_id(c)		((c)->id & ~ID_BIT_AUDIO)
192 	if (vgasr_priv.handler->init)  in vga_switcheroo_enable()
193 		vgasr_priv.handler->init();  in vga_switcheroo_enable()
200 		ret = vgasr_priv.handler->get_client_id(client->pdev);  in vga_switcheroo_enable()
204 		client->id = ret;  in vga_switcheroo_enable()
212 		ret = vgasr_priv.handler->get_client_id(client->vga_dev);  in vga_switcheroo_enable()
216 		client->id = ret | ID_BIT_AUDIO;  in vga_switcheroo_enable()
217 		if (client->ops->gpu_bound)  in vga_switcheroo_enable()
218 			client->ops->gpu_bound(client->pdev, ret);  in vga_switcheroo_enable()
226  * vga_switcheroo_register_handler() - register handler
233  * Return: 0 on success, -EINVAL if a handler was already registered.
242 		return -EINVAL;  in vga_switcheroo_register_handler()
257  * vga_switcheroo_unregister_handler() - unregister handler
278  * vga_switcheroo_handler_flags() - obtain handler flags
293 			   enum vga_switcheroo_client_id id,  in register_client()  argument
302 		return -ENOMEM;  in register_client()
304 	client->pwr_state = VGA_SWITCHEROO_ON;  in register_client()
305 	client->pdev = pdev;  in register_client()
306 	client->ops = ops;  in register_client()
307 	client->id = id;  in register_client()
308 	client->active = active;  in register_client()
309 	client->driver_power_control = driver_power_control;  in register_client()
310 	client->vga_dev = vga_dev;  in register_client()
313 	list_add_tail(&client->list, &vgasr_priv.clients);  in register_client()
326  * vga_switcheroo_register_client - register vga client
332  * Register vga client (GPU). Enable vga_switcheroo if another GPU and a
337  * Return: 0 on success, -ENOMEM on memory allocation error.
350  * vga_switcheroo_register_audio_client - register audio client
355  * Register audio client (audio device on a GPU). The client is assumed
359  * Return: 0 on success, -ENOMEM on memory allocation error, -EINVAL on getting
360  * client id error.
366 	enum vga_switcheroo_client_id id = VGA_SWITCHEROO_UNKNOWN_ID;  in vga_switcheroo_register_audio_client()  local
369 	 * if vga_switcheroo has enabled, that mean two GPU clients and also  in vga_switcheroo_register_audio_client()
370 	 * handler are registered. Get audio client id from bound GPU client  in vga_switcheroo_register_audio_client()
371 	 * id directly, otherwise, set it as VGA_SWITCHEROO_UNKNOWN_ID,  in vga_switcheroo_register_audio_client()
372 	 * it will set to correct id in later when vga_switcheroo_enable()  in vga_switcheroo_register_audio_client()
377 		id = vgasr_priv.handler->get_client_id(vga_dev);  in vga_switcheroo_register_audio_client()
378 		if (id < 0) {  in vga_switcheroo_register_audio_client()
380 			return -EINVAL;  in vga_switcheroo_register_audio_client()
382 		/* notify if GPU has been already bound */  in vga_switcheroo_register_audio_client()
383 		if (ops->gpu_bound)  in vga_switcheroo_register_audio_client()
384 			ops->gpu_bound(pdev, id);  in vga_switcheroo_register_audio_client()
388 	return register_client(pdev, ops, id | ID_BIT_AUDIO, vga_dev,  in vga_switcheroo_register_audio_client()
399 		if (client->pdev == pdev)  in find_client_from_pci()
411 		if (client->id == client_id)  in find_client_from_id()
422 		if (client->active)  in find_active_client()
428  * vga_switcheroo_client_probe_defer() - whether to defer probing a given client
432  * client. Drivers shall invoke this early on in their ->probe callback
433  * and return %-EPROBE_DEFER if it evaluates to %true. Thou shalt not
440 	if ((pdev->class >> 16) == PCI_BASE_CLASS_DISPLAY) {  in vga_switcheroo_client_probe_defer()
442 		 * apple-gmux is needed on pre-retina MacBook Pro  in vga_switcheroo_client_probe_defer()
443 		 * to probe the panel if pdev is the inactive GPU.  in vga_switcheroo_client_probe_defer()
457 	if (client->driver_power_control)  in vga_switcheroo_pwr_state()
458 		if (pm_runtime_enabled(&client->pdev->dev) &&  in vga_switcheroo_pwr_state()
459 		    pm_runtime_active(&client->pdev->dev))  in vga_switcheroo_pwr_state()
464 		return client->pwr_state;  in vga_switcheroo_pwr_state()
468  * vga_switcheroo_get_client_state() - obtain power state of a given client
493  * vga_switcheroo_unregister_client() - unregister client
496  * Unregister client. Disable vga_switcheroo if this is a vga client (GPU).
506 			vgasr_priv.registered_clients--;  in vga_switcheroo_unregister_client()
507 		list_del(&client->list);  in vga_switcheroo_unregister_client()
520  * vga_switcheroo_client_fb_set() - set framebuffer of a given client
535 		client->fb_info = info;  in vga_switcheroo_client_fb_set()
541  * vga_switcheroo_lock_ddc() - temporarily switch DDC lines to a given client
551  * Specifically, %-ENODEV if no handler has registered or if the handler
561 	enum vga_switcheroo_client_id id;  in vga_switcheroo_lock_ddc()  local
564 	if (!vgasr_priv.handler || !vgasr_priv.handler->switch_ddc) {  in vga_switcheroo_lock_ddc()
565 		vgasr_priv.old_ddc_owner = -ENODEV;  in vga_switcheroo_lock_ddc()
566 		return -ENODEV;  in vga_switcheroo_lock_ddc()
569 	id = vgasr_priv.handler->get_client_id(pdev);  in vga_switcheroo_lock_ddc()
570 	vgasr_priv.old_ddc_owner = vgasr_priv.handler->switch_ddc(id);  in vga_switcheroo_lock_ddc()
576  * vga_switcheroo_unlock_ddc() - switch DDC lines back to previous owner
585  * Specifically, %-ENODEV if no handler has registered or if the handler
589  * first is not allowed and will result in %-EINVAL.
593 	enum vga_switcheroo_client_id id;  in vga_switcheroo_unlock_ddc()  local
597 		return -EINVAL;  in vga_switcheroo_unlock_ddc()
600 		id = vgasr_priv.handler->get_client_id(pdev);  in vga_switcheroo_unlock_ddc()
601 		if (vgasr_priv.old_ddc_owner != id)  in vga_switcheroo_unlock_ddc()
602 			ret = vgasr_priv.handler->switch_ddc(  in vga_switcheroo_unlock_ddc()
616  * two GPU drivers and one handler have registered with vga_switcheroo.
622  *   Power on the integrated GPU if necessary, power off the discrete GPU.
632  * * MIGD: Mux-only switch to the integrated graphics device.
633  *   Does not remap console or change the power state of either gpu.
634  *   If the integrated GPU is currently off, the screen will turn black.
637  * * MDIS: Mux-only switch to the discrete graphics device.
640  * the ON and OFF commands are a no-op (see next section).
656 			   client_is_vga(client) ? "" : "-Audio",  in vga_switcheroo_show()
657 			   client->active ? '+' : ' ',  in vga_switcheroo_show()
658 			   client->driver_power_control ? "Dyn" : "",  in vga_switcheroo_show()
660 			   pci_name(client->pdev));  in vga_switcheroo_show()
674 	if (client->driver_power_control)  in vga_switchon()
676 	if (vgasr_priv.handler->power_state)  in vga_switchon()
677 		vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);  in vga_switchon()
679 	client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);  in vga_switchon()
680 	client->pwr_state = VGA_SWITCHEROO_ON;  in vga_switchon()
686 	if (client->driver_power_control)  in vga_switchoff()
689 	client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);  in vga_switchoff()
690 	if (vgasr_priv.handler->power_state)  in vga_switchoff()
691 		vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);  in vga_switchoff()
692 	client->pwr_state = VGA_SWITCHEROO_OFF;  in vga_switchoff()
696 static void set_audio_state(enum vga_switcheroo_client_id id,  in set_audio_state()  argument
701 	client = find_client_from_id(&vgasr_priv.clients, id | ID_BIT_AUDIO);  in set_audio_state()
703 		client->ops->set_gpu_state(client->pdev, state);  in set_audio_state()
718 	vga_set_default_device(new_client->pdev);  in vga_switchto_stage1()
732 	active->active = false;  in vga_switchto_stage2()
734 	/* let HDA controller autosuspend if GPU uses driver power control */  in vga_switchto_stage2()
735 	if (!active->driver_power_control)  in vga_switchto_stage2()
736 		set_audio_state(active->id, VGA_SWITCHEROO_OFF);  in vga_switchto_stage2()
738 	if (new_client->fb_info)  in vga_switchto_stage2()
739 		fbcon_remap_all(new_client->fb_info);  in vga_switchto_stage2()
742 	ret = vgasr_priv.handler->switchto(new_client->id);  in vga_switchto_stage2()
747 	if (new_client->ops->reprobe)  in vga_switchto_stage2()
748 		new_client->ops->reprobe(new_client->pdev);  in vga_switchto_stage2()
753 	/* let HDA controller autoresume if GPU uses driver power control */  in vga_switchto_stage2()
754 	if (!new_client->driver_power_control)  in vga_switchto_stage2()
755 		set_audio_state(new_client->id, VGA_SWITCHEROO_ON);  in vga_switchto_stage2()
757 	new_client->active = true;  in vga_switchto_stage2()
766 		if (!client->ops->can_switch(client->pdev)) {  in check_can_switch()
767 			pr_err("client %x refused switch\n", client->id);  in check_can_switch()
789 		return -EFAULT;  in vga_switcheroo_debugfs_write()
794 		cnt = -EINVAL;  in vga_switcheroo_debugfs_write()
801 			if (client->active || client_is_audio(client))  in vga_switcheroo_debugfs_write()
803 			if (client->driver_power_control)  in vga_switcheroo_debugfs_write()
805 			set_audio_state(client->id, VGA_SWITCHEROO_OFF);  in vga_switcheroo_debugfs_write()
806 			if (client->pwr_state == VGA_SWITCHEROO_ON)  in vga_switcheroo_debugfs_write()
814 			if (client->active || client_is_audio(client))  in vga_switcheroo_debugfs_write()
816 			if (client->driver_power_control)  in vga_switcheroo_debugfs_write()
818 			if (client->pwr_state == VGA_SWITCHEROO_OFF)  in vga_switcheroo_debugfs_write()
820 			set_audio_state(client->id, VGA_SWITCHEROO_ON);  in vga_switcheroo_debugfs_write()
825 	/* request a delayed switch - test can we switch now */  in vga_switcheroo_debugfs_write()
861 		ret = vgasr_priv.handler->switchto(client_id);  in vga_switcheroo_debugfs_write()
866 	if (client->active)  in vga_switcheroo_debugfs_write()
869 	/* okay we want a switch - test if devices are willing to switch */  in vga_switcheroo_debugfs_write()
885 		pr_info("setting delayed switch to client %d\n", client->id);  in vga_switcheroo_debugfs_write()
910 	debugfs_remove_recursive(priv->debugfs_root);  in vga_switcheroo_debugfs_fini()
911 	priv->debugfs_root = NULL;  in vga_switcheroo_debugfs_fini()
917 	if (priv->debugfs_root)  in vga_switcheroo_debugfs_init()
920 	priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);  in vga_switcheroo_debugfs_init()
922 	debugfs_create_file("switch", 0644, priv->debugfs_root, NULL,  in vga_switcheroo_debugfs_init()
927  * vga_switcheroo_process_delayed_switch() - helper for delayed switching
931  * Return: 0 on success. -EINVAL if no delayed switch is pending, if the client
939 	int err = -EINVAL;  in vga_switcheroo_process_delayed_switch()
968  * In this mode of use, the discrete GPU automatically powers up and down at
971  * the ON and OFF commands become a no-op for the discrete GPU.
977  * After the GPU has been suspended, the handler needs to be called to cut
978  * power to the GPU. Likewise it needs to reinstate power before the GPU
980  * which augments the GPU's suspend/resume functions by the requisite
983  * When the audio device resumes, the GPU needs to be woken. This is achieved
985  * GPU. That way, the GPU is kept awake whenever and as long as the audio
988  * On muxed machines, if the mux is initially switched to the discrete GPU,
989  * the user ends up with a black screen when the GPU powers down after boot.
990  * As a workaround, the mux is forced to the integrated GPU on runtime suspend,
991  * cf. https://bugs.freedesktop.org/show_bug.cgi?id=75917
999 	if (!vgasr_priv.handler->power_state)  in vga_switcheroo_power_switch()
1006 	if (!client->driver_power_control)  in vga_switcheroo_power_switch()
1009 	vgasr_priv.handler->power_state(client->id, state);  in vga_switcheroo_power_switch()
1018 	ret = dev->bus->pm->runtime_suspend(dev);  in vga_switcheroo_runtime_suspend()
1022 	if (vgasr_priv.handler->switchto) {  in vga_switcheroo_runtime_suspend()
1024 		vgasr_priv.handler->switchto(VGA_SWITCHEROO_IGD);  in vga_switcheroo_runtime_suspend()
1027 	pci_bus_set_current_state(pdev->bus, PCI_D3cold);  in vga_switcheroo_runtime_suspend()
1040 	pci_resume_bus(pdev->bus);  in vga_switcheroo_runtime_resume()
1041 	return dev->bus->pm->runtime_resume(dev);  in vga_switcheroo_runtime_resume()
1045  * vga_switcheroo_init_domain_pm_ops() - helper for driver power control
1050  * After the GPU has been suspended, the handler needs to be called to cut
1051  * power to the GPU. Likewise it needs to reinstate power before the GPU
1060 	if (dev->bus && dev->bus->pm) {  in vga_switcheroo_init_domain_pm_ops()
1061 		domain->ops = *dev->bus->pm;  in vga_switcheroo_init_domain_pm_ops()
1062 		domain->ops.runtime_suspend = vga_switcheroo_runtime_suspend;  in vga_switcheroo_init_domain_pm_ops()
1063 		domain->ops.runtime_resume = vga_switcheroo_runtime_resume;  in vga_switcheroo_init_domain_pm_ops()
1069 	return -EINVAL;  in vga_switcheroo_init_domain_pm_ops()