vga_switcheroo.h

  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
 36struct 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 */
 53enum 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 */
 68enum 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 */
 86enum 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 */
116struct 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 */
143struct 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)
151void vga_switcheroo_unregister_client(struct pci_dev *dev);
152int vga_switcheroo_register_client(struct pci_dev *dev,
153				   const struct vga_switcheroo_client_ops *ops,
154				   bool driver_power_control);
155int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
156					 const struct vga_switcheroo_client_ops *ops,
157					 struct pci_dev *vga_dev);
158
159void vga_switcheroo_client_fb_set(struct pci_dev *dev,
160				  struct fb_info *info);
161
162int vga_switcheroo_register_handler(const struct vga_switcheroo_handler *handler,
163				    enum vga_switcheroo_handler_flags_t handler_flags);
164void vga_switcheroo_unregister_handler(void);
165enum vga_switcheroo_handler_flags_t vga_switcheroo_handler_flags(void);
166int vga_switcheroo_lock_ddc(struct pci_dev *pdev);
167int vga_switcheroo_unlock_ddc(struct pci_dev *pdev);
168
169int vga_switcheroo_process_delayed_switch(void);
170
171bool vga_switcheroo_client_probe_defer(struct pci_dev *pdev);
172enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *dev);
173
174int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain);
175void vga_switcheroo_fini_domain_pm_ops(struct device *dev);
176#else
177
178static inline void vga_switcheroo_unregister_client(struct pci_dev *dev) {}
179static inline int vga_switcheroo_register_client(struct pci_dev *dev,
180		const struct vga_switcheroo_client_ops *ops, bool driver_power_control) { return 0; }
181static inline void vga_switcheroo_client_fb_set(struct pci_dev *dev, struct fb_info *info) {}
182static inline int vga_switcheroo_register_handler(const struct vga_switcheroo_handler *handler,
183		enum vga_switcheroo_handler_flags_t handler_flags) { return 0; }
184static 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; }
187static inline void vga_switcheroo_unregister_handler(void) {}
188static inline enum vga_switcheroo_handler_flags_t vga_switcheroo_handler_flags(void) { return 0; }
189static inline int vga_switcheroo_lock_ddc(struct pci_dev *pdev) { return -ENODEV; }
190static inline int vga_switcheroo_unlock_ddc(struct pci_dev *pdev) { return -ENODEV; }
191static inline int vga_switcheroo_process_delayed_switch(void) { return 0; }
192static inline bool vga_switcheroo_client_probe_defer(struct pci_dev *pdev) { return false; }
193static inline enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *dev) { return VGA_SWITCHEROO_ON; }
194
195static inline int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
196static inline void vga_switcheroo_fini_domain_pm_ops(struct device *dev) {}
197
198#endif
199#endif /* _LINUX_VGA_SWITCHEROO_H_ */