/*
* vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs
*
* Copyright (c) 2010 Red Hat Inc.
* Author : Dave Airlie <airlied@redhat.com>
*
* Copyright (c) 2015 Lukas Wunner <lukas@wunner.de>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS
* IN THE SOFTWARE.
*
*/
#define pr_fmt(fmt) "vga_switcheroo: " fmt
#include <linux/apple-gmux.h>
#include <linux/console.h>
#include <linux/debugfs.h>
#include <linux/fb.h>
#include <linux/fs.h>
#include <linux/fbcon.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/vgaarb.h>
#include <linux/vga_switcheroo.h>
/**
* DOC: Overview
*
* vga_switcheroo is the Linux subsystem for laptop hybrid graphics.
* These come in two flavors:
*
* * muxed: Dual GPUs with a multiplexer chip to switch outputs between GPUs.
* * muxless: Dual GPUs but only one of them is connected to outputs.
* The other one is merely used to offload rendering, its results
* are copied over PCIe into the framebuffer. On Linux this is
* supported with DRI PRIME.
*
* Hybrid graphics started to appear in the late Naughties and were initially
* all muxed. Newer laptops moved to a muxless architecture for cost reasons.
* A notable exception is the MacBook Pro which continues to use a mux.
* Muxes come with varying capabilities: Some switch only the panel, others
* can also switch external displays. Some switch all display pins at once
* while others can switch just the DDC lines. (To allow EDID probing
* for the inactive GPU.) Also, muxes are often used to cut power to the
* discrete GPU while it is not used.
*
* DRM drivers register GPUs with vga_switcheroo, these are henceforth called
* clients. The mux is called the handler. Muxless machines also register a
* handler to control the power state of the discrete GPU, its ->switchto
* callback is a no-op for obvious reasons. The discrete GPU is often equipped
* with an HDA controller for the HDMI/DP audio signal, this will also
* register as a client so that vga_switcheroo can take care of the correct
* suspend/resume order when changing the discrete GPU's power state. In total
* there can thus be up to three clients: Two vga clients (GPUs) and one audio
* client (on the discrete GPU). The code is mostly prepared to support
* machines with more than two GPUs should they become available.
*
* The GPU to which the outputs are currently switched is called the
* active client in vga_switcheroo parlance. The GPU not in use is the
* inactive client. When the inactive client's DRM driver is loaded,
* it will be unable to probe the panel's EDID and hence depends on
* VBIOS to provide its display modes. If the VBIOS modes are bogus or
* if there is no VBIOS at all (which is common on the MacBook Pro),
* a client may alternatively request that the DDC lines are temporarily
* switched to it, provided that the handler supports this. Switching
* only the DDC lines and not the entire output avoids unnecessary
* flickering.
*/
/**
* struct vga_switcheroo_client - registered client
* @pdev: client pci device
* @fb_info: framebuffer to which console is remapped on switching
* @pwr_state: current power state if manual power control is used.
* For driver power control, call vga_switcheroo_pwr_state().
* @ops: client callbacks
* @id: client identifier. Determining the id requires the handler,
* so gpus are initially assigned VGA_SWITCHEROO_UNKNOWN_ID
* and later given their true id in vga_switcheroo_enable()
* @active: whether the outputs are currently switched to this client
* @driver_power_control: whether power state is controlled by the driver's
* runtime pm. If true, writing ON and OFF to the vga_switcheroo debugfs
* interface is a no-op so as not to interfere with runtime pm
* @list: client list
* @vga_dev: pci device, indicate which GPU is bound to current audio client
*
* Registered client. A client can be either a GPU or an audio device on a GPU.
* For audio clients, the @fb_info and @active members are bogus. For GPU
* clients, the @vga_dev is bogus.
*/
struct vga_switcheroo_client {
struct pci_dev *pdev;
struct fb_info *fb_info;
enum vga_switcheroo_state pwr_state;
const struct vga_switcheroo_client_ops *ops;
enum vga_switcheroo_client_id id;
bool active;
bool driver_power_control;
struct list_head list;
struct pci_dev *vga_dev;
};
/*
* protects access to struct vgasr_priv
*/
static DEFINE_MUTEX(vgasr_mutex);
/**
* struct vgasr_priv - vga_switcheroo private data
* @active: whether vga_switcheroo is enabled.
* Prerequisite is the registration of two GPUs and a handler
* @delayed_switch_active: whether a delayed switch is pending
* @delayed_client_id: client to which a delayed switch is pending
* @debugfs_root: directory for vga_switcheroo debugfs interface
* @registered_clients: number of registered GPUs
* (counting only vga clients, not audio clients)
* @clients: list of registered clients
* @handler: registered handler
* @handler_flags: flags of registered handler
* @mux_hw_lock: protects mux state
* (in particular while DDC lines are temporarily switched)
* @old_ddc_owner: client to which DDC lines will be switched back on unlock
*
* vga_switcheroo private data. Currently only one vga_switcheroo instance
* per system is supported.
*/
struct vgasr_priv {
bool active;
bool delayed_switch_active;
enum vga_switcheroo_client_id delayed_client_id;
struct dentry *debugfs_root;
int registered_clients;
struct list_head clients;
const struct vga_switcheroo_handler *handler;
enum vga_switcheroo_handler_flags_t handler_flags;
struct mutex mux_hw_lock;
int old_ddc_owner;
};
#define ID_BIT_AUDIO 0x100
#define client_is_audio(c) ((c)->id & ID_BIT_AUDIO)
#define client_is_vga(c) (!client_is_audio(c))
#define client_id(c) ((c)->id & ~ID_BIT_AUDIO)
static void vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
/* only one switcheroo per system */
static struct vgasr_priv vgasr_priv = {
.clients = LIST_HEAD_INIT(vgasr_priv.clients),
.mux_hw_lock = __MUTEX_INITIALIZER(vgasr_priv.mux_hw_lock),
};
static bool vga_switcheroo_ready(void)
{
/* we're ready if we get two clients + handler */
return !vgasr_priv.active &&
vgasr_priv.registered_clients == 2 && vgasr_priv.handler;
}
static void vga_switcheroo_enable(void)
{
int ret;
struct vga_switcheroo_client *client;
/* call the handler to init */
if (vgasr_priv.handler->init)
vgasr_priv.handler->init();
list_for_each_entry(client, &vgasr_priv.clients, list) {
if (!client_is_vga(client) ||
client_id(client) != VGA_SWITCHEROO_UNKNOWN_ID)
continue;
ret = vgasr_priv.handler->get_client_id(client->pdev);
if (ret < 0)
return;
client->id = ret;
}
list_for_each_entry(client, &vgasr_priv.clients, list) {
if (!client_is_audio(client) ||
client_id(client) != VGA_SWITCHEROO_UNKNOWN_ID)
continue;
ret = vgasr_priv.handler->get_client_id(client->vga_dev);
if (ret < 0)
return;
client->id = ret | ID_BIT_AUDIO;
if (client->ops->gpu_bound)
client->ops->gpu_bound(client->pdev, ret);
}
vga_switcheroo_debugfs_init(&vgasr_priv);
vgasr_priv.active = true;
}
/**
* vga_switcheroo_register_handler() - register handler
* @handler: handler callbacks
* @handler_flags: handler flags
*
* Register handler. Enable vga_switcheroo if two vga clients have already
* registered.
*
* Return: 0 on success, -EINVAL if a handler was already registered.
*/
int vga_switcheroo_register_handler(
const struct vga_switcheroo_handler *handler,
enum vga_switcheroo_handler_flags_t handler_flags)
{
mutex_lock(&vgasr_mutex);
if (vgasr_priv.handler) {
mutex_unlock(&vgasr_mutex);
return -EINVAL;
}
vgasr_priv.handler = handler;
vgasr_priv.handler_flags = handler_flags;
if (vga_switcheroo_ready()) {
pr_info("enabled\n");
vga_switcheroo_enable();
}
mutex_unlock(&vgasr_mutex);
return 0;
}
EXPORT_SYMBOL(vga_switcheroo_register_handler);
/**
* vga_switcheroo_unregister_handler() - unregister handler
*
* Unregister handler. Disable vga_switcheroo.
*/
void vga_switcheroo_unregister_handler(void)
{
mutex_lock(&vgasr_mutex);
mutex_lock(&vgasr_priv.mux_hw_lock);
vgasr_priv.handler_flags = 0;
vgasr_priv.handler = NULL;
if (vgasr_priv.active) {
pr_info("disabled\n");
vga_switcheroo_debugfs_fini(&vgasr_priv);
vgasr_priv.active = false;
}
mutex_unlock(&vgasr_priv.mux_hw_lock);
mutex_unlock(&vgasr_mutex);
}
EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
/**
* vga_switcheroo_handler_flags() - obtain handler flags
*
* Helper for clients to obtain the handler flags bitmask.
*
* Return: Handler flags. A value of 0 means that no handler is registered
* or that the handler has no special capabilities.
*/
enum vga_switcheroo_handler_flags_t vga_switcheroo_handler_flags(void)
{
return vgasr_priv.handler_flags;
}
EXPORT_SYMBOL(vga_switcheroo_handler_flags);
static int register_client(struct pci_dev *pdev,
const struct vga_switcheroo_client_ops *ops,
enum vga_switcheroo_client_id id,
struct pci_dev *vga_dev,
bool active,
bool driver_power_control)
{
struct vga_switcheroo_client *client;
client = kzalloc(sizeof(*client), GFP_KERNEL);
if (!client)
return -ENOMEM;
client->pwr_state = VGA_SWITCHEROO_ON;
client->pdev = pdev;
client->ops = ops;
client->id = id;
client->active = active;
client->driver_power_control = driver_power_control;
client->vga_dev = vga_dev;
mutex_lock(&vgasr_mutex);
list_add_tail(&client->list, &vgasr_priv.clients);
if (client_is_vga(client))
vgasr_priv.registered_clients++;
if (vga_switcheroo_ready()) {
pr_info("enabled\n");
vga_switcheroo_enable();
}
mutex_unlock(&vgasr_mutex);
return 0;
}
/**
* vga_switcheroo_register_client - register vga client
* @pdev: client pci device
* @ops: client callbacks
* @driver_power_control: whether power state is controlled by the driver's
* runtime pm
*
* Register vga client (GPU). Enable vga_switcheroo if another GPU and a
* handler have already registered. The power state of the client is assumed
* to be ON. Beforehand, vga_switcheroo_client_probe_defer() shall be called
* to ensure that all prerequisites are met.
*
* Return: 0 on success, -ENOMEM on memory allocation error.
*/
int vga_switcheroo_register_client(struct pci_dev *pdev,
const struct vga_switcheroo_client_ops *ops,
bool driver_power_control)
{
return register_client(pdev, ops, VGA_SWITCHEROO_UNKNOWN_ID, NULL,
pdev == vga_default_device(),
driver_power_control);
}
EXPORT_SYMBOL(vga_switcheroo_register_client);
/**
* vga_switcheroo_register_audio_client - register audio client
* @pdev: client pci device
* @ops: client callbacks
* @vga_dev: pci device which is bound to current audio client
*
* Register audio client (audio device on a GPU). The client is assumed
* to use runtime PM. Beforehand, vga_switcheroo_client_probe_defer()
* shall be called to ensure that all prerequisites are met.
*
* Return: 0 on success, -ENOMEM on memory allocation error, -EINVAL on getting
* client id error.
*/
int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
const struct vga_switcheroo_client_ops *ops,
struct pci_dev *vga_dev)
{
enum vga_switcheroo_client_id id = VGA_SWITCHEROO_UNKNOWN_ID;
/*
* if vga_switcheroo has enabled, that mean two GPU clients and also
* handler are registered. Get audio client id from bound GPU client
* id directly, otherwise, set it as VGA_SWITCHEROO_UNKNOWN_ID,
* it will set to correct id in later when vga_switcheroo_enable()
* is called.
*/
mutex_lock(&vgasr_mutex);
if (vgasr_priv.active) {
id = vgasr_priv.handler->get_client_id(vga_dev);
if (id < 0) {
mutex_unlock(&vgasr_mutex);
return -EINVAL;
}
/* notify if GPU has been already bound */
if (ops->gpu_bound)
ops->gpu_bound(pdev, id);
}
mutex_unlock(&vgasr_mutex);
return register_client(pdev, ops, id | ID_BIT_AUDIO, vga_dev,
false, true);
}
EXPORT_SYMBOL(vga_switcheroo_register_audio_client);
static struct vga_switcheroo_client *
find_client_from_pci(struct list_head *head, struct pci_dev *pdev)
{
struct vga_switcheroo_client *client;
list_for_each_entry(client, head, list)
if (client->pdev == pdev)
return client;
return NULL;
}
static struct vga_switcheroo_client *
find_client_from_id(struct list_head *head,
enum vga_switcheroo_client_id client_id)
{
struct vga_switcheroo_client *client;
list_for_each_entry(client, head, list)
if (client->id == client_id)
return client;
return NULL;
}
static struct vga_switcheroo_client *
find_active_client(struct list_head *head)
{
struct vga_switcheroo_client *client;
list_for_each_entry(client, head, list)
if (client->active)
return client;
return NULL;
}
/**
* vga_switcheroo_client_probe_defer() - whether to defer probing a given client
* @pdev: client pci device
*
* Determine whether any prerequisites are not fulfilled to probe a given
* client. Drivers shall invoke this early on in their ->probe callback
* and return %-EPROBE_DEFER if it evaluates to %true. Thou shalt not
* register the client ere thou hast called this.
*
* Return: %true if probing should be deferred, otherwise %false.
*/
bool vga_switcheroo_client_probe_defer(struct pci_dev *pdev)
{
if ((pdev->class >> 16) == PCI_BASE_CLASS_DISPLAY) {
/*
* apple-gmux is needed on pre-retina MacBook Pro
* to probe the panel if pdev is the inactive GPU.
*/
if (apple_gmux_present() && pdev != vga_default_device() &&
!vgasr_priv.handler_flags)
return true;
}
return false;
}
EXPORT_SYMBOL(vga_switcheroo_client_probe_defer);
static enum vga_switcheroo_state
vga_switcheroo_pwr_state(struct vga_switcheroo_client *client)
{
if (client->driver_power_control)
if (pm_runtime_enabled(&client->pdev->dev) &&
pm_runtime_active(&client->pdev->dev))
return VGA_SWITCHEROO_ON;
else
return VGA_SWITCHEROO_OFF;
else
return client->pwr_state;
}
/**
* vga_switcheroo_get_client_state() - obtain power state of a given client
* @pdev: client pci device
*
* Obtain power state of a given client as seen from vga_switcheroo.
* The function is only called from hda_intel.c.
*
* Return: Power state.
*/
enum vga_switcheroo_state vga_switcheroo_get_client_state(struct pci_dev *pdev)
{
struct vga_switcheroo_client *client;
enum vga_switcheroo_state ret;
mutex_lock(&vgasr_mutex);
client = find_client_from_pci(&vgasr_priv.clients, pdev);
if (!client)
ret = VGA_SWITCHEROO_NOT_FOUND;
else
ret = vga_switcheroo_pwr_state(client);
mutex_unlock(&vgasr_mutex);
return ret;
}
EXPORT_SYMBOL(vga_switcheroo_get_client_state);
/**
* vga_switcheroo_unregister_client() - unregister client
* @pdev: client pci device
*
* Unregister client. Disable vga_switcheroo if this is a vga client (GPU).
*/
void vga_switcheroo_unregister_client(struct pci_dev *pdev)
{
struct vga_switcheroo_client *client;
mutex_lock(&vgasr_mutex);
client = find_client_from_pci(&vgasr_priv.clients, pdev);
if (client) {
if (client_is_vga(client))
vgasr_priv.registered_clients--;
list_del(&client->list);
kfree(client);
}
if (vgasr_priv.active && vgasr_priv.registered_clients < 2) {
pr_info("disabled\n");
vga_switcheroo_debugfs_fini(&vgasr_priv);
vgasr_priv.active = false;
}
mutex_unlock(&vgasr_mutex);
}
EXPORT_SYMBOL(vga_switcheroo_unregister_client);
/**
* vga_switcheroo_client_fb_set() - set framebuffer of a given client
* @pdev: client pci device
* @info: framebuffer
*
* Set framebuffer of a given client. The console will be remapped to this
* on switching.
*/
void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
struct fb_info *info)
{
struct vga_switcheroo_client *client;
mutex_lock(&vgasr_mutex);
client = find_client_from_pci(&vgasr_priv.clients, pdev);
if (client)
client->fb_info = info;
mutex_unlock(&vgasr_mutex);
}
EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
/**
* vga_switcheroo_lock_ddc() - temporarily switch DDC lines to a given client
* @pdev: client pci device
*
* Temporarily switch DDC lines to the client identified by @pdev
* (but leave the outputs otherwise switched to where they are).
* This allows the inactive client to probe EDID. The DDC lines must
* afterwards be switched back by calling vga_switcheroo_unlock_ddc(),
* even if this function returns an error.
*
* Return: Previous DDC owner on success or a negative int on error.
* Specifically, %-ENODEV if no handler has registered or if the handler
* does not support switching the DDC lines. Also, a negative value
* returned by the handler is propagated back to the caller.
* The return value has merely an informational purpose for any caller
* which might be interested in it. It is acceptable to ignore the return
* value and simply rely on the result of the subsequent EDID probe,
* which will be %NULL if DDC switching failed.
*/
int vga_switcheroo_lock_ddc(struct pci_dev *pdev)
{
enum vga_switcheroo_client_id id;
mutex_lock(&vgasr_priv.mux_hw_lock);
if (!vgasr_priv.handler || !vgasr_priv.handler->switch_ddc) {
vgasr_priv.old_ddc_owner = -ENODEV;
return -ENODEV;
}
id = vgasr_priv.handler->get_client_id(pdev);
vgasr_priv.old_ddc_owner = vgasr_priv.handler->switch_ddc(id);
return vgasr_priv.old_ddc_owner;
}
EXPORT_SYMBOL(vga_switcheroo_lock_ddc);
/**
* vga_switcheroo_unlock_ddc() - switch DDC lines back to previous owner
* @pdev: client pci device
*
* Switch DDC lines back to the previous owner after calling
* vga_switcheroo_lock_ddc(). This must be called even if
* vga_switcheroo_lock_ddc() returned an error.
*
* Return: Previous DDC owner on success (i.e. the client identifier of @pdev)
* or a negative int on error.
* Specifically, %-ENODEV if no handler has registered or if the handler
* does not support switching the DDC lines. Also, a negative value
* returned by the handler is propagated back to the caller.
* Finally, invoking this function without calling vga_switcheroo_lock_ddc()
* first is not allowed and will result in %-EINVAL.
*/
int vga_switcheroo_unlock_ddc(struct pci_dev *pdev)
{
enum vga_switcheroo_client_id id;
int ret = vgasr_priv.old_ddc_owner;
if (WARN_ON_ONCE(!mutex_is_locked(&vgasr_priv.mux_hw_lock)))
return -EINVAL;
if (vgasr_priv.old_ddc_owner >= 0) {
id = vgasr_priv.handler->get_client_id(pdev);
if (vgasr_priv.old_ddc_owner != id)
ret = vgasr_priv.handler->switch_ddc(
vgasr_priv.old_ddc_owner);
}
mutex_unlock(&vgasr_priv.mux_hw_lock);
return ret;
}
EXPORT_SYMBOL(vga_switcheroo_unlock_ddc);
/**
* DOC: Manual switching and manual power control
*
* In this mode of use, the file /sys/kernel/debug/vgaswitcheroo/switch
* can be read to retrieve the current vga_switcheroo state and commands
* can be written to it to change the state. The file appears as soon as
* two GPU drivers and one handler have registered with vga_switcheroo.
* The following commands are understood:
*
* * OFF: Power off the device not in use.
* * ON: Power on the device not in use.
* * IGD: Switch to the integrated graphics device.
* Power on the integrated GPU if necessary, power off the discrete GPU.
* Prerequisite is that no user space processes (e.g. Xorg, alsactl)
* have opened device files of the GPUs or the audio client. If the
* switch fails, the user may invoke lsof(8) or fuser(1) on /dev/dri/
* and /dev/snd/controlC1 to identify processes blocking the switch.
* * DIS: Switch to the discrete graphics device.
* * DIGD: Delayed switch to the integrated graphics device.
* This will perform the switch once the last user space process has
* closed the device files of the GPUs and the audio client.
* * DDIS: Delayed switch to the discrete graphics device.
* * MIGD: Mux-only switch to the integrated graphics device.
* Does not remap console or change the power state of either gpu.
* If the integrated GPU is currently off, the screen will turn black.
* If it is on, the screen will show whatever happens to be in VRAM.
* Either way, the user has to blindly enter the command to switch back.
* * MDIS: Mux-only switch to the discrete graphics device.
*
* For GPUs whose power state is controlled by the driver's runtime pm,
* the ON and OFF commands are a no-op (see next section).
*
* For muxless machines, the IGD/DIS, DIGD/DDIS and MIGD/MDIS commands
* should not be used.
*/
static int vga_switcheroo_show(struct seq_file *m, void *v)
{
struct vga_switcheroo_client *client;
int i = 0;
mutex_lock(&vgasr_mutex);
list_for_each_entry(client, &vgasr_priv.clients, list) {
seq_printf(m, "%d:%s%s:%c:%s%s:%s\n", i,
client_id(client) == VGA_SWITCHEROO_DIS ? "DIS" :
"IGD",
client_is_vga(client) ? "" : "-Audio",
client->active ? '+' : ' ',
client->driver_power_control ? "Dyn" : "",
vga_switcheroo_pwr_state(client) ? "Pwr" : "Off",
pci_name(client->pdev));
i++;
}
mutex_unlock(&vgasr_mutex);
return 0;
}
static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
{
return single_open(file, vga_switcheroo_show, NULL);
}
static int vga_switchon(struct vga_switcheroo_client *client)
{
if (client->driver_power_control)
return 0;
if (vgasr_priv.handler->power_state)
vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
/* call the driver callback to turn on device */
client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);
client->pwr_state = VGA_SWITCHEROO_ON;
return 0;
}
static int vga_switchoff(struct vga_switcheroo_client *client)
{
if (client->driver_power_control)
return 0;
/* call the driver callback to turn off device */
client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
if (vgasr_priv.handler->power_state)
vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
client->pwr_state = VGA_SWITCHEROO_OFF;
return 0;
}
static void set_audio_state(enum vga_switcheroo_client_id id,
enum vga_switcheroo_state state)
{
struct vga_switcheroo_client *client;
client = find_client_from_id(&vgasr_priv.clients, id | ID_BIT_AUDIO);
if (client)
client->ops->set_gpu_state(client->pdev, state);
}
/* stage one happens before delay */
static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
{
struct vga_switcheroo_client *active;
active = find_active_client(&vgasr_priv.clients);
if (!active)
return 0;
if (vga_switcheroo_pwr_state(new_client) == VGA_SWITCHEROO_OFF)
vga_switchon(new_client);
vga_set_default_device(new_client->pdev);
return 0;
}
/* post delay */
static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
{
int ret;
struct vga_switcheroo_client *active;
active = find_active_client(&vgasr_priv.clients);
if (!active)
return 0;
active->active = false;
/* let HDA controller autosuspend if GPU uses driver power control */
if (!active->driver_power_control)
set_audio_state(active->id, VGA_SWITCHEROO_OFF);
if (new_client->fb_info)
fbcon_remap_all(new_client->fb_info);
mutex_lock(&vgasr_priv.mux_hw_lock);
ret = vgasr_priv.handler->switchto(new_client->id);
mutex_unlock(&vgasr_priv.mux_hw_lock);
if (ret)
return ret;
if (new_client->ops->reprobe)
new_client->ops->reprobe(new_client->pdev);
if (vga_switcheroo_pwr_state(active) == VGA_SWITCHEROO_ON)
vga_switchoff(active);
/* let HDA controller autoresume if GPU uses driver power control */
if (!new_client->driver_power_control)
set_audio_state(new_client->id, VGA_SWITCHEROO_ON);
new_client->active = true;
return 0;
}
static bool check_can_switch(void)
{
struct vga_switcheroo_client *client;
list_for_each_entry(client, &vgasr_priv.clients, list) {
if (!client->ops->can_switch(client->pdev)) {
pr_err("client %x refused switch\n", client->id);
return false;
}
}
return true;
}
static ssize_t
vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char usercmd[64];
int ret;
bool delay = false, can_switch;
bool just_mux = false;
enum vga_switcheroo_client_id client_id = VGA_SWITCHEROO_UNKNOWN_ID;
struct vga_switcheroo_client *client = NULL;
if (cnt > 63)
cnt = 63;
if (copy_from_user(usercmd, ubuf, cnt))
return -EFAULT;
mutex_lock(&vgasr_mutex);
if (!vgasr_priv.active) {
cnt = -EINVAL;
goto out;
}
/* pwr off the device not in use */
if (strncmp(usercmd, "OFF", 3) == 0) {
list_for_each_entry(client, &vgasr_priv.clients, list) {
if (client->active || client_is_audio(client))
continue;
if (client->driver_power_control)
continue;
set_audio_state(client->id, VGA_SWITCHEROO_OFF);
if (client->pwr_state == VGA_SWITCHEROO_ON)
vga_switchoff(client);
}
goto out;
}
/* pwr on the device not in use */
if (strncmp(usercmd, "ON", 2) == 0) {
list_for_each_entry(client, &vgasr_priv.clients, list) {
if (client->active || client_is_audio(client))
continue;
if (client->driver_power_control)
continue;
if (client->pwr_state == VGA_SWITCHEROO_OFF)
vga_switchon(client);
set_audio_state(client->id, VGA_SWITCHEROO_ON);
}
goto out;
}
/* request a delayed switch - test can we switch now */
if (strncmp(usercmd, "DIGD", 4) == 0) {
client_id = VGA_SWITCHEROO_IGD;
delay = true;
}
if (strncmp(usercmd, "DDIS", 4) == 0) {
client_id = VGA_SWITCHEROO_DIS;
delay = true;
}
if (strncmp(usercmd, "IGD", 3) == 0)
client_id = VGA_SWITCHEROO_IGD;
if (strncmp(usercmd, "DIS", 3) == 0)
client_id = VGA_SWITCHEROO_DIS;
if (strncmp(usercmd, "MIGD", 4) == 0) {
just_mux = true;
client_id = VGA_SWITCHEROO_IGD;
}
if (strncmp(usercmd, "MDIS", 4) == 0) {
just_mux = true;
client_id = VGA_SWITCHEROO_DIS;
}
if (client_id == VGA_SWITCHEROO_UNKNOWN_ID)
goto out;
client = find_client_from_id(&vgasr_priv.clients, client_id);
if (!client)
goto out;
vgasr_priv.delayed_switch_active = false;
if (just_mux) {
mutex_lock(&vgasr_priv.mux_hw_lock);
ret = vgasr_priv.handler->switchto(client_id);
mutex_unlock(&vgasr_priv.mux_hw_lock);
goto out;
}
if (client->active)
goto out;
/* okay we want a switch - test if devices are willing to switch */
can_switch = check_can_switch();
if (can_switch == false && delay == false)
goto out;
if (can_switch) {
ret = vga_switchto_stage1(client);
if (ret)
pr_err("switching failed stage 1 %d\n", ret);
ret = vga_switchto_stage2(client);
if (ret)
pr_err("switching failed stage 2 %d\n", ret);
} else {
pr_info("setting delayed switch to client %d\n", client->id);
vgasr_priv.delayed_switch_active = true;
vgasr_priv.delayed_client_id = client_id;
ret = vga_switchto_stage1(client);
if (ret)
pr_err("delayed switching stage 1 failed %d\n", ret);
}
out:
mutex_unlock(&vgasr_mutex);
return cnt;
}
static const struct file_operations vga_switcheroo_debugfs_fops = {
.owner = THIS_MODULE,
.open = vga_switcheroo_debugfs_open,
.write = vga_switcheroo_debugfs_write,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
{
debugfs_remove_recursive(priv->debugfs_root);
priv->debugfs_root = NULL;
}
static void vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
{
/* already initialised */
if (priv->debugfs_root)
return;
priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
debugfs_create_file("switch", 0644, priv->debugfs_root, NULL,
&vga_switcheroo_debugfs_fops);
}
/**
* vga_switcheroo_process_delayed_switch() - helper for delayed switching
*
* Process a delayed switch if one is pending.
*
* Return: 0 on success. -EINVAL if no delayed switch is pending, if the client
* has unregistered in the meantime or if there are other clients blocking the
* switch. If the actual switch fails, an error is reported and 0 is returned.
*/
int vga_switcheroo_process_delayed_switch(void)
{
struct vga_switcheroo_client *client;
int ret;
int err = -EINVAL;
mutex_lock(&vgasr_mutex);
if (!vgasr_priv.delayed_switch_active)
goto err;
pr_info("processing delayed switch to %d\n",
vgasr_priv.delayed_client_id);
client = find_client_from_id(&vgasr_priv.clients,
vgasr_priv.delayed_client_id);
if (!client || !check_can_switch())
goto err;
ret = vga_switchto_stage2(client);
if (ret)
pr_err("delayed switching failed stage 2 %d\n", ret);
vgasr_priv.delayed_switch_active = false;
err = 0;
err:
mutex_unlock(&vgasr_mutex);
return err;
}
EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
/**
* DOC: Driver power control
*
* In this mode of use, the discrete GPU automatically powers up and down at
* the discretion of the driver's runtime pm. On muxed machines, the user may
* still influence the muxer state by way of the debugfs interface, however
* the ON and OFF commands become a no-op for the discrete GPU.
*
* This mode is the default on Nvidia HybridPower/Optimus and ATI PowerXpress.
* Specifying nouveau.runpm=0, radeon.runpm=0 or amdgpu.runpm=0 on the kernel
* command line disables it.
*
* After the GPU has been suspended, the handler needs to be called to cut
* power to the GPU. Likewise it needs to reinstate power before the GPU
* can resume. This is achieved by vga_switcheroo_init_domain_pm_ops(),
* which augments the GPU's suspend/resume functions by the requisite
* calls to the handler.
*
* When the audio device resumes, the GPU needs to be woken. This is achieved
* by a PCI quirk which calls device_link_add() to declare a dependency on the
* GPU. That way, the GPU is kept awake whenever and as long as the audio
* device is in use.
*
* On muxed machines, if the mux is initially switched to the discrete GPU,
* the user ends up with a black screen when the GPU powers down after boot.
* As a workaround, the mux is forced to the integrated GPU on runtime suspend,
* cf. https://bugs.freedesktop.org/show_bug.cgi?id=75917
*/
static void vga_switcheroo_power_switch(struct pci_dev *pdev,
enum vga_switcheroo_state state)
{
struct vga_switcheroo_client *client;
if (!vgasr_priv.handler->power_state)
return;
client = find_client_from_pci(&vgasr_priv.clients, pdev);
if (!client)
return;
if (!client->driver_power_control)
return;
vgasr_priv.handler->power_state(client->id, state);
}
/* switcheroo power domain */
static int vga_switcheroo_runtime_suspend(struct device *dev)
{
struct pci_dev *pdev = to_pci_dev(dev);
int ret;
ret = dev->bus->pm->runtime_suspend(dev);
if (ret)
return ret;
mutex_lock(&vgasr_mutex);
if (vgasr_priv.handler->switchto) {
mutex_lock(&vgasr_priv.mux_hw_lock);
vgasr_priv.handler->switchto(VGA_SWITCHEROO_IGD);
mutex_unlock(&vgasr_priv.mux_hw_lock);
}
pci_bus_set_current_state(pdev->bus, PCI_D3cold);
vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_OFF);
mutex_unlock(&vgasr_mutex);
return 0;
}
static int vga_switcheroo_runtime_resume(struct device *dev)
{
struct pci_dev *pdev = to_pci_dev(dev);
mutex_lock(&vgasr_mutex);
vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_ON);
mutex_unlock(&vgasr_mutex);
pci_resume_bus(pdev->bus);
return dev->bus->pm->runtime_resume(dev);
}
/**
* vga_switcheroo_init_domain_pm_ops() - helper for driver power control
* @dev: vga client device
* @domain: power domain
*
* Helper for GPUs whose power state is controlled by the driver's runtime pm.
* After the GPU has been suspended, the handler needs to be called to cut
* power to the GPU. Likewise it needs to reinstate power before the GPU
* can resume. To this end, this helper augments the suspend/resume functions
* by the requisite calls to the handler. It needs only be called on platforms
* where the power switch is separate to the device being powered down.
*/
int vga_switcheroo_init_domain_pm_ops(struct device *dev,
struct dev_pm_domain *domain)
{
/* copy over all the bus versions */
if (dev->bus && dev->bus->pm) {
domain->ops = *dev->bus->pm;
domain->ops.runtime_suspend = vga_switcheroo_runtime_suspend;
domain->ops.runtime_resume = vga_switcheroo_runtime_resume;
dev_pm_domain_set(dev, domain);
return 0;
}
dev_pm_domain_set(dev, NULL);
return -EINVAL;
}
EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_ops);
void vga_switcheroo_fini_domain_pm_ops(struct device *dev)
{
dev_pm_domain_set(dev, NULL);
}
EXPORT_SYMBOL(vga_switcheroo_fini_domain_pm_ops);
