linux/drivers/gpu/vga/vga_switcheroo.c
Takashi Iwai c91c3faea5 vga_switcheroo: Enable/disable audio clients at the right time
The audio clients have to be disabled before disabling the VGA and
switching.  Similarly, enabling the audio client should be done at
last.  Otherwise the audio-side operation stalls, eventually leading
to Oops or lockups.

Tested-by: Jörg-Volker Peetz <jvpeetz@web.de>
Acked-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2012-06-09 12:14:43 +02:00

555 lines
14 KiB
C

/*
* Copyright (c) 2010 Red Hat Inc.
* Author : Dave Airlie <airlied@redhat.com>
*
*
* Licensed under GPLv2
*
* vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs
Switcher interface - methods require for ATPX and DCM
- switchto - this throws the output MUX switch
- discrete_set_power - sets the power state for the discrete card
GPU driver interface
- set_gpu_state - this should do the equiv of s/r for the card
- this should *not* set the discrete power state
- switch_check - check if the device is in a position to switch now
*/
#include <linux/module.h>
#include <linux/dmi.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/fs.h>
#include <linux/debugfs.h>
#include <linux/fb.h>
#include <linux/pci.h>
#include <linux/vga_switcheroo.h>
#include <linux/vgaarb.h>
struct vga_switcheroo_client {
struct pci_dev *pdev;
struct fb_info *fb_info;
int pwr_state;
const struct vga_switcheroo_client_ops *ops;
int id;
bool active;
struct list_head list;
};
static DEFINE_MUTEX(vgasr_mutex);
struct vgasr_priv {
bool active;
bool delayed_switch_active;
enum vga_switcheroo_client_id delayed_client_id;
struct dentry *debugfs_root;
struct dentry *switch_file;
int registered_clients;
struct list_head clients;
struct vga_switcheroo_handler *handler;
};
#define ID_BIT_AUDIO 0x100
#define client_is_audio(c) ((c)->id & ID_BIT_AUDIO)
#define client_is_vga(c) ((c)->id == -1 || !client_is_audio(c))
#define client_id(c) ((c)->id & ~ID_BIT_AUDIO)
static int 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),
};
int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
{
mutex_lock(&vgasr_mutex);
if (vgasr_priv.handler) {
mutex_unlock(&vgasr_mutex);
return -EINVAL;
}
vgasr_priv.handler = handler;
mutex_unlock(&vgasr_mutex);
return 0;
}
EXPORT_SYMBOL(vga_switcheroo_register_handler);
void vga_switcheroo_unregister_handler(void)
{
mutex_lock(&vgasr_mutex);
vgasr_priv.handler = NULL;
mutex_unlock(&vgasr_mutex);
}
EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
static void vga_switcheroo_enable(void)
{
int ret;
struct vga_switcheroo_client *client;
/* call the handler to init */
vgasr_priv.handler->init();
list_for_each_entry(client, &vgasr_priv.clients, list) {
if (client->id != -1)
continue;
ret = vgasr_priv.handler->get_client_id(client->pdev);
if (ret < 0)
return;
client->id = ret;
}
vga_switcheroo_debugfs_init(&vgasr_priv);
vgasr_priv.active = true;
}
static int register_client(struct pci_dev *pdev,
const struct vga_switcheroo_client_ops *ops,
int id, bool active)
{
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;
mutex_lock(&vgasr_mutex);
list_add_tail(&client->list, &vgasr_priv.clients);
if (client_is_vga(client))
vgasr_priv.registered_clients++;
/* if we get two clients + handler */
if (!vgasr_priv.active &&
vgasr_priv.registered_clients == 2 && vgasr_priv.handler) {
printk(KERN_INFO "vga_switcheroo: enabled\n");
vga_switcheroo_enable();
}
mutex_unlock(&vgasr_mutex);
return 0;
}
int vga_switcheroo_register_client(struct pci_dev *pdev,
const struct vga_switcheroo_client_ops *ops)
{
return register_client(pdev, ops, -1,
pdev == vga_default_device());
}
EXPORT_SYMBOL(vga_switcheroo_register_client);
int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
const struct vga_switcheroo_client_ops *ops,
int id, bool active)
{
return register_client(pdev, ops, id | ID_BIT_AUDIO, active);
}
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, int 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 && client_is_vga(client))
return client;
return NULL;
}
int vga_switcheroo_get_client_state(struct pci_dev *pdev)
{
struct vga_switcheroo_client *client;
client = find_client_from_pci(&vgasr_priv.clients, pdev);
if (!client)
return VGA_SWITCHEROO_NOT_FOUND;
if (!vgasr_priv.active)
return VGA_SWITCHEROO_INIT;
return client->pwr_state;
}
EXPORT_SYMBOL(vga_switcheroo_get_client_state);
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) {
printk(KERN_INFO "vga_switcheroo: disabled\n");
vga_switcheroo_debugfs_fini(&vgasr_priv);
vgasr_priv.active = false;
}
mutex_unlock(&vgasr_mutex);
}
EXPORT_SYMBOL(vga_switcheroo_unregister_client);
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);
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\n", i,
client_id(client) == VGA_SWITCHEROO_DIS ? "DIS" : "IGD",
client_is_vga(client) ? "" : "-Audio",
client->active ? '+' : ' ',
client->pwr_state ? "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 (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)
{
/* 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(int id, int state)
{
struct vga_switcheroo_client *client;
client = find_client_from_id(&vgasr_priv.clients, id | ID_BIT_AUDIO);
if (client && client->pwr_state != state) {
client->ops->set_gpu_state(client->pdev, state);
client->pwr_state = 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 (new_client->pwr_state == 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;
set_audio_state(active->id, VGA_SWITCHEROO_OFF);
if (new_client->fb_info) {
struct fb_event event;
event.info = new_client->fb_info;
fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
}
ret = vgasr_priv.handler->switchto(new_client->id);
if (ret)
return ret;
if (new_client->ops->reprobe)
new_client->ops->reprobe(new_client->pdev);
if (active->pwr_state == VGA_SWITCHEROO_ON)
vga_switchoff(active);
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)) {
printk(KERN_ERR "vga_switcheroo: 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];
const char *pdev_name;
int ret;
bool delay = false, can_switch;
bool just_mux = false;
int client_id = -1;
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;
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->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 == -1)
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) {
ret = vgasr_priv.handler->switchto(client_id);
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) {
pdev_name = pci_name(client->pdev);
ret = vga_switchto_stage1(client);
if (ret)
printk(KERN_ERR "vga_switcheroo: switching failed stage 1 %d\n", ret);
ret = vga_switchto_stage2(client);
if (ret)
printk(KERN_ERR "vga_switcheroo: switching failed stage 2 %d\n", ret);
} else {
printk(KERN_INFO "vga_switcheroo: 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)
printk(KERN_ERR "vga_switcheroo: 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)
{
if (priv->switch_file) {
debugfs_remove(priv->switch_file);
priv->switch_file = NULL;
}
if (priv->debugfs_root) {
debugfs_remove(priv->debugfs_root);
priv->debugfs_root = NULL;
}
}
static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
{
/* already initialised */
if (priv->debugfs_root)
return 0;
priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
if (!priv->debugfs_root) {
printk(KERN_ERR "vga_switcheroo: Cannot create /sys/kernel/debug/vgaswitcheroo\n");
goto fail;
}
priv->switch_file = debugfs_create_file("switch", 0644,
priv->debugfs_root, NULL, &vga_switcheroo_debugfs_fops);
if (!priv->switch_file) {
printk(KERN_ERR "vga_switcheroo: cannot create /sys/kernel/debug/vgaswitcheroo/switch\n");
goto fail;
}
return 0;
fail:
vga_switcheroo_debugfs_fini(priv);
return -1;
}
int vga_switcheroo_process_delayed_switch(void)
{
struct vga_switcheroo_client *client;
const char *pdev_name;
int ret;
int err = -EINVAL;
mutex_lock(&vgasr_mutex);
if (!vgasr_priv.delayed_switch_active)
goto err;
printk(KERN_INFO "vga_switcheroo: 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;
pdev_name = pci_name(client->pdev);
ret = vga_switchto_stage2(client);
if (ret)
printk(KERN_ERR "vga_switcheroo: 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);