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Originally by Seth Forshee <seth.forshee@canonical.com>, 2012-10-04: During graphics driver initialization it's useful to be able to mux only the DDC to the inactive client in order to read the EDID. Add a switch_ddc callback to allow capable handlers to provide this functionality, and add vga_switcheroo_switch_ddc() to allow DRM to mux only the DDC. Modified by Dave Airlie <airlied@gmail.com>, 2012-12-22: I can't figure out why I didn't like this, but I rewrote this [...] to lock/unlock the ddc lines [...]. I think I'd prefer something like that otherwise the interface got really ugly. Modified by Lukas Wunner <lukas@wunner.de>, 2015-04 - 2015-10: Change semantics of ->switch_ddc handler callback to return previous DDC owner. Original version tried to determine previous DDC owner with find_active_client() but this fails if the inactive client registers before the active client. Don't lock vgasr_mutex in _lock_ddc() / _unlock_ddc(), it can cause deadlocks because (a) during switch (with vgasr_mutex already held), GPU is woken and probes its outputs, tries to re-acquire vgasr_mutex to lock DDC lines; (b) Likewise during switch, GPU is suspended and calls cancel_delayed_work_sync() to stop output polling, if poll task is running at this moment we may wait forever for it to finish. Instead, lock mux_hw_lock when unregistering the handler because the only reason why we'd want to lock vgasr_mutex in _lock_ddc() / _unlock_ddc() is to block the handler from disappearing while DDC lines are switched. Also acquire mux_hw_lock in stage2 to avoid race condition where reading the EDID and switching happens simultaneously. Likewise on MIGD / MDIS commands and on runtime suspend. v2.1: Overhaul locking, squash commits (Daniel Vetter) v2.2: Readability improvements (Thierry Reding) v2.3: Overhaul locking once more v2.4: Retain semantics of ->switchto handler callback to switch all pins, including DDC (Daniel Vetter) v5: Rename ddc_lock to mux_hw_lock: Since we acquire this both when calling ->switch_ddc and ->switchto, it protects not just access to the DDC lines but to the mux in general. This is in line with the DRM convention to use low-level locks to avoid concurrent hw access (e.g. i2c, dp_aux) which are often called hw_lock (Daniel Vetter) Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=88861 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61115 Tested-by: Lukas Wunner <lukas@wunner.de> [MBP 9,1 2012 intel IVB + nvidia GK107 pre-retina 15"] Cc: Seth Forshee <seth.forshee@canonical.com> Cc: Dave Airlie <airlied@gmail.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/e81ae9722b84c5ed591805fee3ea6dbf5dc6c4b3.1452525860.git.lukas@wunner.de
201 lines
8.7 KiB
C
201 lines
8.7 KiB
C
/*
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* vga_switcheroo.h - Support for laptop with dual GPU using one set of outputs
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*
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* Copyright (c) 2010 Red Hat Inc.
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* Author : Dave Airlie <airlied@redhat.com>
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*
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* Copyright (c) 2015 Lukas Wunner <lukas@wunner.de>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS
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* IN THE SOFTWARE.
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*
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*/
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#ifndef _LINUX_VGA_SWITCHEROO_H_
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#define _LINUX_VGA_SWITCHEROO_H_
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#include <linux/fb.h>
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struct pci_dev;
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/**
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* enum vga_switcheroo_handler_flags_t - handler flags bitmask
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* @VGA_SWITCHEROO_CAN_SWITCH_DDC: whether the handler is able to switch the
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* DDC lines separately. This signals to clients that they should call
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* drm_get_edid_switcheroo() to probe the EDID
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* @VGA_SWITCHEROO_NEEDS_EDP_CONFIG: whether the handler is unable to switch
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* the AUX channel separately. This signals to clients that the active
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* GPU needs to train the link and communicate the link parameters to the
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* inactive GPU (mediated by vga_switcheroo). The inactive GPU may then
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* skip the AUX handshake and set up its output with these pre-calibrated
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* values (DisplayPort specification v1.1a, section 2.5.3.3)
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*
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* Handler flags bitmask. Used by handlers to declare their capabilities upon
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* registering with vga_switcheroo.
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*/
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enum vga_switcheroo_handler_flags_t {
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VGA_SWITCHEROO_CAN_SWITCH_DDC = (1 << 0),
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VGA_SWITCHEROO_NEEDS_EDP_CONFIG = (1 << 1),
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};
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/**
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* enum vga_switcheroo_state - client power state
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* @VGA_SWITCHEROO_OFF: off
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* @VGA_SWITCHEROO_ON: on
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* @VGA_SWITCHEROO_NOT_FOUND: client has not registered with vga_switcheroo.
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* Only used in vga_switcheroo_get_client_state() which in turn is only
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* called from hda_intel.c
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*
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* Client power state.
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*/
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enum vga_switcheroo_state {
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VGA_SWITCHEROO_OFF,
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VGA_SWITCHEROO_ON,
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/* below are referred only from vga_switcheroo_get_client_state() */
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VGA_SWITCHEROO_NOT_FOUND,
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};
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/**
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* enum vga_switcheroo_client_id - client identifier
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* @VGA_SWITCHEROO_UNKNOWN_ID: initial identifier assigned to vga clients.
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* Determining the id requires the handler, so GPUs are given their
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* true id in a delayed fashion in vga_switcheroo_enable()
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* @VGA_SWITCHEROO_IGD: integrated graphics device
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* @VGA_SWITCHEROO_DIS: discrete graphics device
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* @VGA_SWITCHEROO_MAX_CLIENTS: currently no more than two GPUs are supported
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*
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* Client identifier. Audio clients use the same identifier & 0x100.
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*/
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enum vga_switcheroo_client_id {
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VGA_SWITCHEROO_UNKNOWN_ID = -1,
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VGA_SWITCHEROO_IGD,
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VGA_SWITCHEROO_DIS,
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VGA_SWITCHEROO_MAX_CLIENTS,
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};
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/**
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* struct vga_switcheroo_handler - handler callbacks
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* @init: initialize handler.
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* Optional. This gets called when vga_switcheroo is enabled, i.e. when
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* two vga clients have registered. It allows the handler to perform
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* some delayed initialization that depends on the existence of the
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* vga clients. Currently only the radeon and amdgpu drivers use this.
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* The return value is ignored
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* @switchto: switch outputs to given client.
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* Mandatory. For muxless machines this should be a no-op. Returning 0
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* denotes success, anything else failure (in which case the switch is
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* aborted)
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* @switch_ddc: switch DDC lines to given client.
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* Optional. Should return the previous DDC owner on success or a
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* negative int on failure
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* @power_state: cut or reinstate power of given client.
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* Optional. The return value is ignored
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* @get_client_id: determine if given pci device is integrated or discrete GPU.
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* Mandatory
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*
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* Handler callbacks. The multiplexer itself. The @switchto and @get_client_id
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* methods are mandatory, all others may be set to NULL.
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*/
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struct vga_switcheroo_handler {
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int (*init)(void);
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int (*switchto)(enum vga_switcheroo_client_id id);
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int (*switch_ddc)(enum vga_switcheroo_client_id id);
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int (*power_state)(enum vga_switcheroo_client_id id,
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enum vga_switcheroo_state state);
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enum vga_switcheroo_client_id (*get_client_id)(struct pci_dev *pdev);
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};
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/**
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* struct vga_switcheroo_client_ops - client callbacks
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* @set_gpu_state: do the equivalent of suspend/resume for the card.
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* Mandatory. This should not cut power to the discrete GPU,
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* which is the job of the handler
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* @reprobe: poll outputs.
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* Optional. This gets called after waking the GPU and switching
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* the outputs to it
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* @can_switch: check if the device is in a position to switch now.
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* Mandatory. The client should return false if a user space process
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* has one of its device files open
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*
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* Client callbacks. A client can be either a GPU or an audio device on a GPU.
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* The @set_gpu_state and @can_switch methods are mandatory, @reprobe may be
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* set to NULL. For audio clients, the @reprobe member is bogus.
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*/
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struct vga_switcheroo_client_ops {
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void (*set_gpu_state)(struct pci_dev *dev, enum vga_switcheroo_state);
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void (*reprobe)(struct pci_dev *dev);
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bool (*can_switch)(struct pci_dev *dev);
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};
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#if defined(CONFIG_VGA_SWITCHEROO)
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void vga_switcheroo_unregister_client(struct pci_dev *dev);
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int vga_switcheroo_register_client(struct pci_dev *dev,
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const struct vga_switcheroo_client_ops *ops,
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bool driver_power_control);
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int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
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const struct vga_switcheroo_client_ops *ops,
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enum vga_switcheroo_client_id id);
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void vga_switcheroo_client_fb_set(struct pci_dev *dev,
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struct fb_info *info);
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int vga_switcheroo_register_handler(const struct vga_switcheroo_handler *handler,
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enum vga_switcheroo_handler_flags_t handler_flags);
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void vga_switcheroo_unregister_handler(void);
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enum vga_switcheroo_handler_flags_t vga_switcheroo_handler_flags(void);
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int vga_switcheroo_lock_ddc(struct pci_dev *pdev);
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int vga_switcheroo_unlock_ddc(struct pci_dev *pdev);
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int vga_switcheroo_process_delayed_switch(void);
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enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *dev);
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void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum vga_switcheroo_state dynamic);
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int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain);
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void vga_switcheroo_fini_domain_pm_ops(struct device *dev);
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int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain);
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#else
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static inline void vga_switcheroo_unregister_client(struct pci_dev *dev) {}
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static inline int vga_switcheroo_register_client(struct pci_dev *dev,
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const struct vga_switcheroo_client_ops *ops, bool driver_power_control) { return 0; }
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static inline void vga_switcheroo_client_fb_set(struct pci_dev *dev, struct fb_info *info) {}
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static inline int vga_switcheroo_register_handler(const struct vga_switcheroo_handler *handler,
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enum vga_switcheroo_handler_flags_t handler_flags) { return 0; }
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static inline int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
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const struct vga_switcheroo_client_ops *ops,
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enum vga_switcheroo_client_id id) { return 0; }
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static inline void vga_switcheroo_unregister_handler(void) {}
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static inline enum vga_switcheroo_handler_flags_t vga_switcheroo_handler_flags(void) { return 0; }
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static inline int vga_switcheroo_lock_ddc(struct pci_dev *pdev) { return -ENODEV; }
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static inline int vga_switcheroo_unlock_ddc(struct pci_dev *pdev) { return -ENODEV; }
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static inline int vga_switcheroo_process_delayed_switch(void) { return 0; }
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static inline enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *dev) { return VGA_SWITCHEROO_ON; }
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static inline void vga_switcheroo_set_dynamic_switch(struct pci_dev *pdev, enum vga_switcheroo_state dynamic) {}
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static inline int vga_switcheroo_init_domain_pm_ops(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
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static inline void vga_switcheroo_fini_domain_pm_ops(struct device *dev) {}
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static inline int vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev, struct dev_pm_domain *domain) { return -EINVAL; }
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#endif
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#endif /* _LINUX_VGA_SWITCHEROO_H_ */
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