linux/drivers/gpu/vga/vga_switcheroo.c
Jiri Slaby 8c88e50bcf gpu: vga_switcheroo, fix lock imbalance
Stanse found that one error path in vga_switcheroo_debugfs_write omits to
unlock vgasr_mutex.  Fix that.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-04-28 18:41:52 +10:00

453 lines
11 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>
struct vga_switcheroo_client {
struct pci_dev *pdev;
struct fb_info *fb_info;
int pwr_state;
void (*set_gpu_state)(struct pci_dev *pdev, enum vga_switcheroo_state);
bool (*can_switch)(struct pci_dev *pdev);
int id;
bool active;
};
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 vga_switcheroo_client clients[VGA_SWITCHEROO_MAX_CLIENTS];
struct vga_switcheroo_handler *handler;
};
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;
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 i;
int ret;
/* call the handler to init */
vgasr_priv.handler->init();
for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
ret = vgasr_priv.handler->get_client_id(vgasr_priv.clients[i].pdev);
if (ret < 0)
return;
vgasr_priv.clients[i].id = ret;
}
vga_switcheroo_debugfs_init(&vgasr_priv);
vgasr_priv.active = true;
}
int vga_switcheroo_register_client(struct pci_dev *pdev,
void (*set_gpu_state)(struct pci_dev *pdev, enum vga_switcheroo_state),
bool (*can_switch)(struct pci_dev *pdev))
{
int index;
mutex_lock(&vgasr_mutex);
/* don't do IGD vs DIS here */
if (vgasr_priv.registered_clients & 1)
index = 1;
else
index = 0;
vgasr_priv.clients[index].pwr_state = VGA_SWITCHEROO_ON;
vgasr_priv.clients[index].pdev = pdev;
vgasr_priv.clients[index].set_gpu_state = set_gpu_state;
vgasr_priv.clients[index].can_switch = can_switch;
vgasr_priv.clients[index].id = -1;
if (pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW)
vgasr_priv.clients[index].active = true;
vgasr_priv.registered_clients |= (1 << index);
/* if we get two clients + handler */
if (vgasr_priv.registered_clients == 0x3 && vgasr_priv.handler) {
printk(KERN_INFO "vga_switcheroo: enabled\n");
vga_switcheroo_enable();
}
mutex_unlock(&vgasr_mutex);
return 0;
}
EXPORT_SYMBOL(vga_switcheroo_register_client);
void vga_switcheroo_unregister_client(struct pci_dev *pdev)
{
int i;
mutex_lock(&vgasr_mutex);
for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
if (vgasr_priv.clients[i].pdev == pdev) {
vgasr_priv.registered_clients &= ~(1 << i);
break;
}
}
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)
{
int i;
mutex_lock(&vgasr_mutex);
for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
if (vgasr_priv.clients[i].pdev == pdev) {
vgasr_priv.clients[i].fb_info = info;
break;
}
}
mutex_unlock(&vgasr_mutex);
}
EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
static int vga_switcheroo_show(struct seq_file *m, void *v)
{
int i;
mutex_lock(&vgasr_mutex);
for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
seq_printf(m, "%d:%c:%s:%s\n", i,
vgasr_priv.clients[i].active ? '+' : ' ',
vgasr_priv.clients[i].pwr_state ? "Pwr" : "Off",
pci_name(vgasr_priv.clients[i].pdev));
}
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)
{
int ret;
ret = vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
/* call the driver callback to turn on device */
client->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->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
client->pwr_state = VGA_SWITCHEROO_OFF;
return 0;
}
static int vga_switchto(struct vga_switcheroo_client *new_client)
{
int ret;
int i;
struct vga_switcheroo_client *active = NULL;
if (new_client->active == true)
return 0;
for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
if (vgasr_priv.clients[i].active == true) {
active = &vgasr_priv.clients[i];
break;
}
}
if (!active)
return 0;
/* power up the first device */
ret = pci_enable_device(new_client->pdev);
if (ret)
return ret;
if (new_client->pwr_state == VGA_SWITCHEROO_OFF)
vga_switchon(new_client);
/* swap shadow resource to denote boot VGA device has changed so X starts on new device */
active->active = false;
active->pdev->resource[PCI_ROM_RESOURCE].flags &= ~IORESOURCE_ROM_SHADOW;
new_client->pdev->resource[PCI_ROM_RESOURCE].flags |= IORESOURCE_ROM_SHADOW;
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 (active->pwr_state == VGA_SWITCHEROO_ON)
vga_switchoff(active);
new_client->active = true;
return 0;
}
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 i, ret;
bool delay = false, can_switch;
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) {
for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
if (vgasr_priv.clients[i].active)
continue;
if (vgasr_priv.clients[i].pwr_state == VGA_SWITCHEROO_ON)
vga_switchoff(&vgasr_priv.clients[i]);
}
goto out;
}
/* pwr on the device not in use */
if (strncmp(usercmd, "ON", 2) == 0) {
for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
if (vgasr_priv.clients[i].active)
continue;
if (vgasr_priv.clients[i].pwr_state == VGA_SWITCHEROO_OFF)
vga_switchon(&vgasr_priv.clients[i]);
}
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 (client_id == -1)
goto out;
for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
if (vgasr_priv.clients[i].id == client_id) {
client = &vgasr_priv.clients[i];
break;
}
}
vgasr_priv.delayed_switch_active = false;
/* okay we want a switch - test if devices are willing to switch */
can_switch = true;
for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
can_switch = vgasr_priv.clients[i].can_switch(vgasr_priv.clients[i].pdev);
if (can_switch == false) {
printk(KERN_ERR "vga_switcheroo: client %d refused switch\n", i);
break;
}
}
if (can_switch == false && delay == false)
goto out;
if (can_switch == true) {
pdev_name = pci_name(client->pdev);
ret = vga_switchto(client);
if (ret)
printk(KERN_ERR "vga_switcheroo: switching failed %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;
/* we should at least power up the card to
make the switch faster */
if (client->pwr_state == VGA_SWITCHEROO_OFF)
vga_switchon(client);
}
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 = NULL;
const char *pdev_name;
bool can_switch = true;
int i;
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);
for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
if (vgasr_priv.clients[i].id == vgasr_priv.delayed_client_id)
client = &vgasr_priv.clients[i];
can_switch = vgasr_priv.clients[i].can_switch(vgasr_priv.clients[i].pdev);
if (can_switch == false) {
printk(KERN_ERR "vga_switcheroo: client %d refused switch\n", i);
break;
}
}
if (can_switch == false || client == NULL)
goto err;
pdev_name = pci_name(client->pdev);
ret = vga_switchto(client);
if (ret)
printk(KERN_ERR "vga_switcheroo: delayed switching failed %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);