1 /*
2  * vga_switcheroo.h - Support for laptop with dual GPU using one set of outputs
3  *
4  * Copyright (c) 2010 Red Hat Inc.
5  * Author : Dave Airlie <airlied@redhat.com>
6  *
7  * Copyright (c) 2015 Lukas Wunner <lukas@wunner.de>
8  *
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:
15  *
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
18  * Software.
19  *
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
26  * DEALINGS
27  * IN THE SOFTWARE.
28  *
29  */
30 
31 #ifndef _LINUX_VGA_SWITCHEROO_H_
32 #define _LINUX_VGA_SWITCHEROO_H_
33 
34 #include <linux/fb.h>
35 
36 struct pci_dev;
37 
38 /**
39  * enum vga_switcheroo_handler_flags_t - handler flags bitmask
40  * @VGA_SWITCHEROO_CAN_SWITCH_DDC: whether the handler is able to switch the
41  * 	DDC lines separately. This signals to clients that they should call
42  * 	drm_get_edid_switcheroo() to probe the EDID
43  * @VGA_SWITCHEROO_NEEDS_EDP_CONFIG: whether the handler is unable to switch
44  * 	the AUX channel separately. This signals to clients that the active
45  * 	GPU needs to train the link and communicate the link parameters to the
46  * 	inactive GPU (mediated by vga_switcheroo). The inactive GPU may then
47  * 	skip the AUX handshake and set up its output with these pre-calibrated
48  * 	values (DisplayPort specification v1.1a, section 2.5.3.3)
49  *
50  * Handler flags bitmask. Used by handlers to declare their capabilities upon
51  * registering with vga_switcheroo.
52  */
53 enum vga_switcheroo_handler_flags_t {
54 	VGA_SWITCHEROO_CAN_SWITCH_DDC	= (1 << 0),
55 	VGA_SWITCHEROO_NEEDS_EDP_CONFIG	= (1 << 1),
56 };
57 
58 /**
59  * enum vga_switcheroo_state - client power state
60  * @VGA_SWITCHEROO_OFF: off
61  * @VGA_SWITCHEROO_ON: on
62  * @VGA_SWITCHEROO_NOT_FOUND: client has not registered with vga_switcheroo.
63  * 	Only used in vga_switcheroo_get_client_state() which in turn is only
64  * 	called from hda_intel.c
65  *
66  * Client power state.
67  */
68 enum vga_switcheroo_state {
69 	VGA_SWITCHEROO_OFF,
70 	VGA_SWITCHEROO_ON,
71 	/* below are referred only from vga_switcheroo_get_client_state() */
72 	VGA_SWITCHEROO_NOT_FOUND,
73 };
74 
75 /**
76  * enum vga_switcheroo_client_id - client identifier
77  * @VGA_SWITCHEROO_UNKNOWN_ID: initial identifier assigned to vga clients.
78  * 	Determining the id requires the handler, so GPUs are given their
79  * 	true id in a delayed fashion in vga_switcheroo_enable()
80  * @VGA_SWITCHEROO_IGD: integrated graphics device
81  * @VGA_SWITCHEROO_DIS: discrete graphics device
82  * @VGA_SWITCHEROO_MAX_CLIENTS: currently no more than two GPUs are supported
83  *
84  * Client identifier. Audio clients use the same identifier & 0x100.
85  */
86 enum vga_switcheroo_client_id {
87 	VGA_SWITCHEROO_UNKNOWN_ID = 0x1000,
88 	VGA_SWITCHEROO_IGD = 0,
89 	VGA_SWITCHEROO_DIS,
90 	VGA_SWITCHEROO_MAX_CLIENTS,
91 };
92 
93 /**
94  * struct vga_switcheroo_handler - handler callbacks
95  * @init: initialize handler.
96  * 	Optional. This gets called when vga_switcheroo is enabled, i.e. when
97  * 	two vga clients have registered. It allows the handler to perform
98  * 	some delayed initialization that depends on the existence of the
99  * 	vga clients. Currently only the radeon and amdgpu drivers use this.
100  * 	The return value is ignored
101  * @switchto: switch outputs to given client.
102  * 	Mandatory. For muxless machines this should be a no-op. Returning 0
103  * 	denotes success, anything else failure (in which case the switch is
104  * 	aborted)
105  * @switch_ddc: switch DDC lines to given client.
106  * 	Optional. Should return the previous DDC owner on success or a
107  * 	negative int on failure
108  * @power_state: cut or reinstate power of given client.
109  * 	Optional. The return value is ignored
110  * @get_client_id: determine if given pci device is integrated or discrete GPU.
111  * 	Mandatory
112  *
113  * Handler callbacks. The multiplexer itself. The @switchto and @get_client_id
114  * methods are mandatory, all others may be set to NULL.
115  */
116 struct vga_switcheroo_handler {
117 	int (*init)(void);
118 	int (*switchto)(enum vga_switcheroo_client_id id);
119 	int (*switch_ddc)(enum vga_switcheroo_client_id id);
120 	int (*power_state)(enum vga_switcheroo_client_id id,
121 			   enum vga_switcheroo_state state);
122 	enum vga_switcheroo_client_id (*get_client_id)(struct pci_dev *pdev);
123 };
124 
125 /**
126  * struct vga_switcheroo_client_ops - client callbacks
127  * @set_gpu_state: do the equivalent of suspend/resume for the card.
128  * 	Mandatory. This should not cut power to the discrete GPU,
129  * 	which is the job of the handler
130  * @reprobe: poll outputs.
131  * 	Optional. This gets called after waking the GPU and switching
132  * 	the outputs to it
133  * @can_switch: check if the device is in a position to switch now.
134  * 	Mandatory. The client should return false if a user space process
135  * 	has one of its device files open
136  * @gpu_bound: notify the client id to audio client when the GPU is bound.
137  *
138  * Client callbacks. A client can be either a GPU or an audio device on a GPU.
139  * The @set_gpu_state and @can_switch methods are mandatory, @reprobe may be
140  * set to NULL. For audio clients, the @reprobe member is bogus.
141  * OTOH, @gpu_bound is only for audio clients, and not used for GPU clients.
142  */
143 struct vga_switcheroo_client_ops {
144 	void (*set_gpu_state)(struct pci_dev *dev, enum vga_switcheroo_state);
145 	void (*reprobe)(struct pci_dev *dev);
146 	bool (*can_switch)(struct pci_dev *dev);
147 	void (*gpu_bound)(struct pci_dev *dev, enum vga_switcheroo_client_id);
148 };
149 
150 #if defined(CONFIG_VGA_SWITCHEROO)
151 void vga_switcheroo_unregister_client(struct pci_dev *dev);
152 int vga_switcheroo_register_client(struct pci_dev *dev,
153 				   const struct vga_switcheroo_client_ops *ops,
154 				   bool driver_power_control);
155 int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
156 					 const struct vga_switcheroo_client_ops *ops,
157 					 struct pci_dev *vga_dev);
158 
159 void vga_switcheroo_client_fb_set(struct pci_dev *dev,
160 				  struct fb_info *info);
161 
162 int vga_switcheroo_register_handler(const struct vga_switcheroo_handler *handler,
163 				    enum vga_switcheroo_handler_flags_t handler_flags);
164 void vga_switcheroo_unregister_handler(void);
165 enum vga_switcheroo_handler_flags_t vga_switcheroo_handler_flags(void);
166 int vga_switcheroo_lock_ddc(struct pci_dev *pdev);
167 int vga_switcheroo_unlock_ddc(struct pci_dev *pdev);
168 
169 int vga_switcheroo_process_delayed_switch(void);
170 
171 bool vga_switcheroo_client_probe_defer(struct pci_dev *pdev);
172 enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *dev);
173 
174 int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain);
175 void vga_switcheroo_fini_domain_pm_ops(struct device *dev);
176 #else
177 
vga_switcheroo_unregister_client(struct pci_dev * dev)178 static inline void vga_switcheroo_unregister_client(struct pci_dev *dev) {}
vga_switcheroo_register_client(struct pci_dev * dev,const struct vga_switcheroo_client_ops * ops,bool driver_power_control)179 static inline int vga_switcheroo_register_client(struct pci_dev *dev,
180 		const struct vga_switcheroo_client_ops *ops, bool driver_power_control) { return 0; }
vga_switcheroo_client_fb_set(struct pci_dev * dev,struct fb_info * info)181 static inline void vga_switcheroo_client_fb_set(struct pci_dev *dev, struct fb_info *info) {}
vga_switcheroo_register_handler(const struct vga_switcheroo_handler * handler,enum vga_switcheroo_handler_flags_t handler_flags)182 static inline int vga_switcheroo_register_handler(const struct vga_switcheroo_handler *handler,
183 		enum vga_switcheroo_handler_flags_t handler_flags) { return 0; }
vga_switcheroo_register_audio_client(struct pci_dev * pdev,const struct vga_switcheroo_client_ops * ops,struct pci_dev * vga_dev)184 static inline int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
185 	const struct vga_switcheroo_client_ops *ops,
186 	struct pci_dev *vga_dev) { return 0; }
vga_switcheroo_unregister_handler(void)187 static inline void vga_switcheroo_unregister_handler(void) {}
vga_switcheroo_handler_flags(void)188 static inline enum vga_switcheroo_handler_flags_t vga_switcheroo_handler_flags(void) { return 0; }
vga_switcheroo_lock_ddc(struct pci_dev * pdev)189 static inline int vga_switcheroo_lock_ddc(struct pci_dev *pdev) { return -ENODEV; }
vga_switcheroo_unlock_ddc(struct pci_dev * pdev)190 static inline int vga_switcheroo_unlock_ddc(struct pci_dev *pdev) { return -ENODEV; }
vga_switcheroo_process_delayed_switch(void)191 static inline int vga_switcheroo_process_delayed_switch(void) { return 0; }
vga_switcheroo_client_probe_defer(struct pci_dev * pdev)192 static inline bool vga_switcheroo_client_probe_defer(struct pci_dev *pdev) { return false; }
vga_switcheroo_get_client_state(struct pci_dev * dev)193 static inline enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *dev) { return VGA_SWITCHEROO_ON; }
194 
vga_switcheroo_init_domain_pm_ops(struct device * dev,struct dev_pm_domain * domain)195 static inline int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
vga_switcheroo_fini_domain_pm_ops(struct device * dev)196 static inline void vga_switcheroo_fini_domain_pm_ops(struct device *dev) {}
197 
198 #endif
199 #endif /* _LINUX_VGA_SWITCHEROO_H_ */
200