2 * Copyright (c) 2010 Red Hat Inc.
3 * Author : Dave Airlie <airlied@redhat.com>
8 * vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs
10 Switcher interface - methods require for ATPX and DCM
11 - switchto - this throws the output MUX switch
12 - discrete_set_power - sets the power state for the discrete card
15 - set_gpu_state - this should do the equiv of s/r for the card
16 - this should *not* set the discrete power state
17 - switch_check - check if the device is in a position to switch now
20 #include <linux/module.h>
21 #include <linux/dmi.h>
22 #include <linux/seq_file.h>
23 #include <linux/uaccess.h>
25 #include <linux/debugfs.h>
28 #include <linux/pci.h>
29 #include <linux/vga_switcheroo.h>
31 #include <linux/vgaarb.h>
33 struct vga_switcheroo_client {
35 struct fb_info *fb_info;
37 const struct vga_switcheroo_client_ops *ops;
40 struct list_head list;
43 static DEFINE_MUTEX(vgasr_mutex);
48 bool delayed_switch_active;
49 enum vga_switcheroo_client_id delayed_client_id;
51 struct dentry *debugfs_root;
52 struct dentry *switch_file;
54 int registered_clients;
55 struct list_head clients;
57 struct vga_switcheroo_handler *handler;
60 #define ID_BIT_AUDIO 0x100
61 #define client_is_audio(c) ((c)->id & ID_BIT_AUDIO)
62 #define client_is_vga(c) ((c)->id == -1 || !client_is_audio(c))
63 #define client_id(c) ((c)->id & ~ID_BIT_AUDIO)
65 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
66 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
68 /* only one switcheroo per system */
69 static struct vgasr_priv vgasr_priv = {
70 .clients = LIST_HEAD_INIT(vgasr_priv.clients),
73 int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
75 mutex_lock(&vgasr_mutex);
76 if (vgasr_priv.handler) {
77 mutex_unlock(&vgasr_mutex);
81 vgasr_priv.handler = handler;
82 mutex_unlock(&vgasr_mutex);
85 EXPORT_SYMBOL(vga_switcheroo_register_handler);
87 void vga_switcheroo_unregister_handler(void)
89 mutex_lock(&vgasr_mutex);
90 vgasr_priv.handler = NULL;
91 mutex_unlock(&vgasr_mutex);
93 EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
95 static void vga_switcheroo_enable(void)
98 struct vga_switcheroo_client *client;
100 /* call the handler to init */
101 vgasr_priv.handler->init();
103 list_for_each_entry(client, &vgasr_priv.clients, list) {
104 if (client->id != -1)
106 ret = vgasr_priv.handler->get_client_id(client->pdev);
112 vga_switcheroo_debugfs_init(&vgasr_priv);
113 vgasr_priv.active = true;
116 static int register_client(struct pci_dev *pdev,
117 const struct vga_switcheroo_client_ops *ops,
120 struct vga_switcheroo_client *client;
122 client = kzalloc(sizeof(*client), GFP_KERNEL);
126 client->pwr_state = VGA_SWITCHEROO_ON;
130 client->active = active;
132 mutex_lock(&vgasr_mutex);
133 list_add_tail(&client->list, &vgasr_priv.clients);
134 if (client_is_vga(client))
135 vgasr_priv.registered_clients++;
137 /* if we get two clients + handler */
138 if (!vgasr_priv.active &&
139 vgasr_priv.registered_clients == 2 && vgasr_priv.handler) {
140 printk(KERN_INFO "vga_switcheroo: enabled\n");
141 vga_switcheroo_enable();
143 mutex_unlock(&vgasr_mutex);
147 int vga_switcheroo_register_client(struct pci_dev *pdev,
148 const struct vga_switcheroo_client_ops *ops)
150 return register_client(pdev, ops, -1,
151 pdev == vga_default_device());
153 EXPORT_SYMBOL(vga_switcheroo_register_client);
155 int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
156 const struct vga_switcheroo_client_ops *ops,
159 return register_client(pdev, ops, id | ID_BIT_AUDIO, active);
161 EXPORT_SYMBOL(vga_switcheroo_register_audio_client);
163 static struct vga_switcheroo_client *
164 find_client_from_pci(struct list_head *head, struct pci_dev *pdev)
166 struct vga_switcheroo_client *client;
167 list_for_each_entry(client, head, list)
168 if (client->pdev == pdev)
173 static struct vga_switcheroo_client *
174 find_client_from_id(struct list_head *head, int client_id)
176 struct vga_switcheroo_client *client;
177 list_for_each_entry(client, head, list)
178 if (client->id == client_id)
183 static struct vga_switcheroo_client *
184 find_active_client(struct list_head *head)
186 struct vga_switcheroo_client *client;
187 list_for_each_entry(client, head, list)
188 if (client->active && client_is_vga(client))
193 int vga_switcheroo_get_client_state(struct pci_dev *pdev)
195 struct vga_switcheroo_client *client;
197 client = find_client_from_pci(&vgasr_priv.clients, pdev);
199 return VGA_SWITCHEROO_NOT_FOUND;
200 if (!vgasr_priv.active)
201 return VGA_SWITCHEROO_INIT;
202 return client->pwr_state;
204 EXPORT_SYMBOL(vga_switcheroo_get_client_state);
206 void vga_switcheroo_unregister_client(struct pci_dev *pdev)
208 struct vga_switcheroo_client *client;
210 mutex_lock(&vgasr_mutex);
211 client = find_client_from_pci(&vgasr_priv.clients, pdev);
213 if (client_is_vga(client))
214 vgasr_priv.registered_clients--;
215 list_del(&client->list);
218 if (vgasr_priv.active && vgasr_priv.registered_clients < 2) {
219 printk(KERN_INFO "vga_switcheroo: disabled\n");
220 vga_switcheroo_debugfs_fini(&vgasr_priv);
221 vgasr_priv.active = false;
223 mutex_unlock(&vgasr_mutex);
225 EXPORT_SYMBOL(vga_switcheroo_unregister_client);
227 void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
228 struct fb_info *info)
230 struct vga_switcheroo_client *client;
232 mutex_lock(&vgasr_mutex);
233 client = find_client_from_pci(&vgasr_priv.clients, pdev);
235 client->fb_info = info;
236 mutex_unlock(&vgasr_mutex);
238 EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
240 static int vga_switcheroo_show(struct seq_file *m, void *v)
242 struct vga_switcheroo_client *client;
244 mutex_lock(&vgasr_mutex);
245 list_for_each_entry(client, &vgasr_priv.clients, list) {
246 seq_printf(m, "%d:%s%s:%c:%s:%s\n", i,
247 client_id(client) == VGA_SWITCHEROO_DIS ? "DIS" : "IGD",
248 client_is_vga(client) ? "" : "-Audio",
249 client->active ? '+' : ' ',
250 client->pwr_state ? "Pwr" : "Off",
251 pci_name(client->pdev));
254 mutex_unlock(&vgasr_mutex);
258 static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
260 return single_open(file, vga_switcheroo_show, NULL);
263 static int vga_switchon(struct vga_switcheroo_client *client)
265 if (vgasr_priv.handler->power_state)
266 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
267 /* call the driver callback to turn on device */
268 client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);
269 client->pwr_state = VGA_SWITCHEROO_ON;
273 static int vga_switchoff(struct vga_switcheroo_client *client)
275 /* call the driver callback to turn off device */
276 client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
277 if (vgasr_priv.handler->power_state)
278 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
279 client->pwr_state = VGA_SWITCHEROO_OFF;
283 static void set_audio_state(int id, int state)
285 struct vga_switcheroo_client *client;
287 client = find_client_from_id(&vgasr_priv.clients, id | ID_BIT_AUDIO);
288 if (client && client->pwr_state != state) {
289 client->ops->set_gpu_state(client->pdev, state);
290 client->pwr_state = state;
294 /* stage one happens before delay */
295 static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
297 struct vga_switcheroo_client *active;
299 active = find_active_client(&vgasr_priv.clients);
303 if (new_client->pwr_state == VGA_SWITCHEROO_OFF)
304 vga_switchon(new_client);
306 vga_set_default_device(new_client->pdev);
311 static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
314 struct vga_switcheroo_client *active;
316 active = find_active_client(&vgasr_priv.clients);
320 active->active = false;
322 set_audio_state(active->id, VGA_SWITCHEROO_OFF);
324 if (new_client->fb_info) {
325 struct fb_event event;
326 event.info = new_client->fb_info;
327 fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
330 ret = vgasr_priv.handler->switchto(new_client->id);
334 if (new_client->ops->reprobe)
335 new_client->ops->reprobe(new_client->pdev);
337 if (active->pwr_state == VGA_SWITCHEROO_ON)
338 vga_switchoff(active);
340 set_audio_state(new_client->id, VGA_SWITCHEROO_ON);
342 new_client->active = true;
346 static bool check_can_switch(void)
348 struct vga_switcheroo_client *client;
350 list_for_each_entry(client, &vgasr_priv.clients, list) {
351 if (!client->ops->can_switch(client->pdev)) {
352 printk(KERN_ERR "vga_switcheroo: client %x refused switch\n", client->id);
360 vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
361 size_t cnt, loff_t *ppos)
364 const char *pdev_name;
366 bool delay = false, can_switch;
367 bool just_mux = false;
369 struct vga_switcheroo_client *client = NULL;
374 if (copy_from_user(usercmd, ubuf, cnt))
377 mutex_lock(&vgasr_mutex);
379 if (!vgasr_priv.active) {
384 /* pwr off the device not in use */
385 if (strncmp(usercmd, "OFF", 3) == 0) {
386 list_for_each_entry(client, &vgasr_priv.clients, list) {
387 if (client->active || client_is_audio(client))
389 set_audio_state(client->id, VGA_SWITCHEROO_OFF);
390 if (client->pwr_state == VGA_SWITCHEROO_ON)
391 vga_switchoff(client);
395 /* pwr on the device not in use */
396 if (strncmp(usercmd, "ON", 2) == 0) {
397 list_for_each_entry(client, &vgasr_priv.clients, list) {
398 if (client->active || client_is_audio(client))
400 if (client->pwr_state == VGA_SWITCHEROO_OFF)
401 vga_switchon(client);
402 set_audio_state(client->id, VGA_SWITCHEROO_ON);
407 /* request a delayed switch - test can we switch now */
408 if (strncmp(usercmd, "DIGD", 4) == 0) {
409 client_id = VGA_SWITCHEROO_IGD;
413 if (strncmp(usercmd, "DDIS", 4) == 0) {
414 client_id = VGA_SWITCHEROO_DIS;
418 if (strncmp(usercmd, "IGD", 3) == 0)
419 client_id = VGA_SWITCHEROO_IGD;
421 if (strncmp(usercmd, "DIS", 3) == 0)
422 client_id = VGA_SWITCHEROO_DIS;
424 if (strncmp(usercmd, "MIGD", 4) == 0) {
426 client_id = VGA_SWITCHEROO_IGD;
428 if (strncmp(usercmd, "MDIS", 4) == 0) {
430 client_id = VGA_SWITCHEROO_DIS;
435 client = find_client_from_id(&vgasr_priv.clients, client_id);
439 vgasr_priv.delayed_switch_active = false;
442 ret = vgasr_priv.handler->switchto(client_id);
449 /* okay we want a switch - test if devices are willing to switch */
450 can_switch = check_can_switch();
452 if (can_switch == false && delay == false)
456 pdev_name = pci_name(client->pdev);
457 ret = vga_switchto_stage1(client);
459 printk(KERN_ERR "vga_switcheroo: switching failed stage 1 %d\n", ret);
461 ret = vga_switchto_stage2(client);
463 printk(KERN_ERR "vga_switcheroo: switching failed stage 2 %d\n", ret);
466 printk(KERN_INFO "vga_switcheroo: setting delayed switch to client %d\n", client->id);
467 vgasr_priv.delayed_switch_active = true;
468 vgasr_priv.delayed_client_id = client_id;
470 ret = vga_switchto_stage1(client);
472 printk(KERN_ERR "vga_switcheroo: delayed switching stage 1 failed %d\n", ret);
476 mutex_unlock(&vgasr_mutex);
480 static const struct file_operations vga_switcheroo_debugfs_fops = {
481 .owner = THIS_MODULE,
482 .open = vga_switcheroo_debugfs_open,
483 .write = vga_switcheroo_debugfs_write,
486 .release = single_release,
489 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
491 if (priv->switch_file) {
492 debugfs_remove(priv->switch_file);
493 priv->switch_file = NULL;
495 if (priv->debugfs_root) {
496 debugfs_remove(priv->debugfs_root);
497 priv->debugfs_root = NULL;
501 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
503 /* already initialised */
504 if (priv->debugfs_root)
506 priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
508 if (!priv->debugfs_root) {
509 printk(KERN_ERR "vga_switcheroo: Cannot create /sys/kernel/debug/vgaswitcheroo\n");
513 priv->switch_file = debugfs_create_file("switch", 0644,
514 priv->debugfs_root, NULL, &vga_switcheroo_debugfs_fops);
515 if (!priv->switch_file) {
516 printk(KERN_ERR "vga_switcheroo: cannot create /sys/kernel/debug/vgaswitcheroo/switch\n");
521 vga_switcheroo_debugfs_fini(priv);
525 int vga_switcheroo_process_delayed_switch(void)
527 struct vga_switcheroo_client *client;
528 const char *pdev_name;
532 mutex_lock(&vgasr_mutex);
533 if (!vgasr_priv.delayed_switch_active)
536 printk(KERN_INFO "vga_switcheroo: processing delayed switch to %d\n", vgasr_priv.delayed_client_id);
538 client = find_client_from_id(&vgasr_priv.clients,
539 vgasr_priv.delayed_client_id);
540 if (!client || !check_can_switch())
543 pdev_name = pci_name(client->pdev);
544 ret = vga_switchto_stage2(client);
546 printk(KERN_ERR "vga_switcheroo: delayed switching failed stage 2 %d\n", ret);
548 vgasr_priv.delayed_switch_active = false;
551 mutex_unlock(&vgasr_mutex);
554 EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);