xref: /linux/drivers/gpu/vga/vga_switcheroo.c (revision 26b0d14106954ae46d2f4f7eec3481828a210f7d)
1 /*
2  * Copyright (c) 2010 Red Hat Inc.
3  * Author : Dave Airlie <airlied@redhat.com>
4  *
5  *
6  * Licensed under GPLv2
7  *
8  * vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs
9 
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
13 
14  GPU driver interface
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
18  */
19 
20 #include <linux/module.h>
21 #include <linux/dmi.h>
22 #include <linux/seq_file.h>
23 #include <linux/uaccess.h>
24 #include <linux/fs.h>
25 #include <linux/debugfs.h>
26 #include <linux/fb.h>
27 
28 #include <linux/pci.h>
29 #include <linux/vga_switcheroo.h>
30 
31 #include <linux/vgaarb.h>
32 
33 struct vga_switcheroo_client {
34 	struct pci_dev *pdev;
35 	struct fb_info *fb_info;
36 	int pwr_state;
37 	const struct vga_switcheroo_client_ops *ops;
38 	int id;
39 	bool active;
40 	struct list_head list;
41 };
42 
43 static DEFINE_MUTEX(vgasr_mutex);
44 
45 struct vgasr_priv {
46 
47 	bool active;
48 	bool delayed_switch_active;
49 	enum vga_switcheroo_client_id delayed_client_id;
50 
51 	struct dentry *debugfs_root;
52 	struct dentry *switch_file;
53 
54 	int registered_clients;
55 	struct list_head clients;
56 
57 	struct vga_switcheroo_handler *handler;
58 };
59 
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)
64 
65 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
66 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
67 
68 /* only one switcheroo per system */
69 static struct vgasr_priv vgasr_priv = {
70 	.clients = LIST_HEAD_INIT(vgasr_priv.clients),
71 };
72 
73 int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
74 {
75 	mutex_lock(&vgasr_mutex);
76 	if (vgasr_priv.handler) {
77 		mutex_unlock(&vgasr_mutex);
78 		return -EINVAL;
79 	}
80 
81 	vgasr_priv.handler = handler;
82 	mutex_unlock(&vgasr_mutex);
83 	return 0;
84 }
85 EXPORT_SYMBOL(vga_switcheroo_register_handler);
86 
87 void vga_switcheroo_unregister_handler(void)
88 {
89 	mutex_lock(&vgasr_mutex);
90 	vgasr_priv.handler = NULL;
91 	mutex_unlock(&vgasr_mutex);
92 }
93 EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
94 
95 static void vga_switcheroo_enable(void)
96 {
97 	int ret;
98 	struct vga_switcheroo_client *client;
99 
100 	/* call the handler to init */
101 	vgasr_priv.handler->init();
102 
103 	list_for_each_entry(client, &vgasr_priv.clients, list) {
104 		if (client->id != -1)
105 			continue;
106 		ret = vgasr_priv.handler->get_client_id(client->pdev);
107 		if (ret < 0)
108 			return;
109 
110 		client->id = ret;
111 	}
112 	vga_switcheroo_debugfs_init(&vgasr_priv);
113 	vgasr_priv.active = true;
114 }
115 
116 static int register_client(struct pci_dev *pdev,
117 			   const struct vga_switcheroo_client_ops *ops,
118 			   int id, bool active)
119 {
120 	struct vga_switcheroo_client *client;
121 
122 	client = kzalloc(sizeof(*client), GFP_KERNEL);
123 	if (!client)
124 		return -ENOMEM;
125 
126 	client->pwr_state = VGA_SWITCHEROO_ON;
127 	client->pdev = pdev;
128 	client->ops = ops;
129 	client->id = id;
130 	client->active = active;
131 
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++;
136 
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();
142 	}
143 	mutex_unlock(&vgasr_mutex);
144 	return 0;
145 }
146 
147 int vga_switcheroo_register_client(struct pci_dev *pdev,
148 				   const struct vga_switcheroo_client_ops *ops)
149 {
150 	return register_client(pdev, ops, -1,
151 			       pdev == vga_default_device());
152 }
153 EXPORT_SYMBOL(vga_switcheroo_register_client);
154 
155 int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
156 					 const struct vga_switcheroo_client_ops *ops,
157 					 int id, bool active)
158 {
159 	return register_client(pdev, ops, id | ID_BIT_AUDIO, active);
160 }
161 EXPORT_SYMBOL(vga_switcheroo_register_audio_client);
162 
163 static struct vga_switcheroo_client *
164 find_client_from_pci(struct list_head *head, struct pci_dev *pdev)
165 {
166 	struct vga_switcheroo_client *client;
167 	list_for_each_entry(client, head, list)
168 		if (client->pdev == pdev)
169 			return client;
170 	return NULL;
171 }
172 
173 static struct vga_switcheroo_client *
174 find_client_from_id(struct list_head *head, int client_id)
175 {
176 	struct vga_switcheroo_client *client;
177 	list_for_each_entry(client, head, list)
178 		if (client->id == client_id)
179 			return client;
180 	return NULL;
181 }
182 
183 static struct vga_switcheroo_client *
184 find_active_client(struct list_head *head)
185 {
186 	struct vga_switcheroo_client *client;
187 	list_for_each_entry(client, head, list)
188 		if (client->active && client_is_vga(client))
189 			return client;
190 	return NULL;
191 }
192 
193 int vga_switcheroo_get_client_state(struct pci_dev *pdev)
194 {
195 	struct vga_switcheroo_client *client;
196 
197 	client = find_client_from_pci(&vgasr_priv.clients, pdev);
198 	if (!client)
199 		return VGA_SWITCHEROO_NOT_FOUND;
200 	if (!vgasr_priv.active)
201 		return VGA_SWITCHEROO_INIT;
202 	return client->pwr_state;
203 }
204 EXPORT_SYMBOL(vga_switcheroo_get_client_state);
205 
206 void vga_switcheroo_unregister_client(struct pci_dev *pdev)
207 {
208 	struct vga_switcheroo_client *client;
209 
210 	mutex_lock(&vgasr_mutex);
211 	client = find_client_from_pci(&vgasr_priv.clients, pdev);
212 	if (client) {
213 		if (client_is_vga(client))
214 			vgasr_priv.registered_clients--;
215 		list_del(&client->list);
216 		kfree(client);
217 	}
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;
222 	}
223 	mutex_unlock(&vgasr_mutex);
224 }
225 EXPORT_SYMBOL(vga_switcheroo_unregister_client);
226 
227 void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
228 				 struct fb_info *info)
229 {
230 	struct vga_switcheroo_client *client;
231 
232 	mutex_lock(&vgasr_mutex);
233 	client = find_client_from_pci(&vgasr_priv.clients, pdev);
234 	if (client)
235 		client->fb_info = info;
236 	mutex_unlock(&vgasr_mutex);
237 }
238 EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
239 
240 static int vga_switcheroo_show(struct seq_file *m, void *v)
241 {
242 	struct vga_switcheroo_client *client;
243 	int i = 0;
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));
252 		i++;
253 	}
254 	mutex_unlock(&vgasr_mutex);
255 	return 0;
256 }
257 
258 static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
259 {
260 	return single_open(file, vga_switcheroo_show, NULL);
261 }
262 
263 static int vga_switchon(struct vga_switcheroo_client *client)
264 {
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;
270 	return 0;
271 }
272 
273 static int vga_switchoff(struct vga_switcheroo_client *client)
274 {
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;
280 	return 0;
281 }
282 
283 static void set_audio_state(int id, int state)
284 {
285 	struct vga_switcheroo_client *client;
286 
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;
291 	}
292 }
293 
294 /* stage one happens before delay */
295 static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
296 {
297 	struct vga_switcheroo_client *active;
298 
299 	active = find_active_client(&vgasr_priv.clients);
300 	if (!active)
301 		return 0;
302 
303 	if (new_client->pwr_state == VGA_SWITCHEROO_OFF)
304 		vga_switchon(new_client);
305 
306 	vga_set_default_device(new_client->pdev);
307 	return 0;
308 }
309 
310 /* post delay */
311 static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
312 {
313 	int ret;
314 	struct vga_switcheroo_client *active;
315 
316 	active = find_active_client(&vgasr_priv.clients);
317 	if (!active)
318 		return 0;
319 
320 	active->active = false;
321 
322 	set_audio_state(active->id, VGA_SWITCHEROO_OFF);
323 
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);
328 	}
329 
330 	ret = vgasr_priv.handler->switchto(new_client->id);
331 	if (ret)
332 		return ret;
333 
334 	if (new_client->ops->reprobe)
335 		new_client->ops->reprobe(new_client->pdev);
336 
337 	if (active->pwr_state == VGA_SWITCHEROO_ON)
338 		vga_switchoff(active);
339 
340 	set_audio_state(new_client->id, VGA_SWITCHEROO_ON);
341 
342 	new_client->active = true;
343 	return 0;
344 }
345 
346 static bool check_can_switch(void)
347 {
348 	struct vga_switcheroo_client *client;
349 
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);
353 			return false;
354 		}
355 	}
356 	return true;
357 }
358 
359 static ssize_t
360 vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
361 			     size_t cnt, loff_t *ppos)
362 {
363 	char usercmd[64];
364 	const char *pdev_name;
365 	int ret;
366 	bool delay = false, can_switch;
367 	bool just_mux = false;
368 	int client_id = -1;
369 	struct vga_switcheroo_client *client = NULL;
370 
371 	if (cnt > 63)
372 		cnt = 63;
373 
374 	if (copy_from_user(usercmd, ubuf, cnt))
375 		return -EFAULT;
376 
377 	mutex_lock(&vgasr_mutex);
378 
379 	if (!vgasr_priv.active) {
380 		cnt = -EINVAL;
381 		goto out;
382 	}
383 
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))
388 				continue;
389 			set_audio_state(client->id, VGA_SWITCHEROO_OFF);
390 			if (client->pwr_state == VGA_SWITCHEROO_ON)
391 				vga_switchoff(client);
392 		}
393 		goto out;
394 	}
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))
399 				continue;
400 			if (client->pwr_state == VGA_SWITCHEROO_OFF)
401 				vga_switchon(client);
402 			set_audio_state(client->id, VGA_SWITCHEROO_ON);
403 		}
404 		goto out;
405 	}
406 
407 	/* request a delayed switch - test can we switch now */
408 	if (strncmp(usercmd, "DIGD", 4) == 0) {
409 		client_id = VGA_SWITCHEROO_IGD;
410 		delay = true;
411 	}
412 
413 	if (strncmp(usercmd, "DDIS", 4) == 0) {
414 		client_id = VGA_SWITCHEROO_DIS;
415 		delay = true;
416 	}
417 
418 	if (strncmp(usercmd, "IGD", 3) == 0)
419 		client_id = VGA_SWITCHEROO_IGD;
420 
421 	if (strncmp(usercmd, "DIS", 3) == 0)
422 		client_id = VGA_SWITCHEROO_DIS;
423 
424 	if (strncmp(usercmd, "MIGD", 4) == 0) {
425 		just_mux = true;
426 		client_id = VGA_SWITCHEROO_IGD;
427 	}
428 	if (strncmp(usercmd, "MDIS", 4) == 0) {
429 		just_mux = true;
430 		client_id = VGA_SWITCHEROO_DIS;
431 	}
432 
433 	if (client_id == -1)
434 		goto out;
435 	client = find_client_from_id(&vgasr_priv.clients, client_id);
436 	if (!client)
437 		goto out;
438 
439 	vgasr_priv.delayed_switch_active = false;
440 
441 	if (just_mux) {
442 		ret = vgasr_priv.handler->switchto(client_id);
443 		goto out;
444 	}
445 
446 	if (client->active)
447 		goto out;
448 
449 	/* okay we want a switch - test if devices are willing to switch */
450 	can_switch = check_can_switch();
451 
452 	if (can_switch == false && delay == false)
453 		goto out;
454 
455 	if (can_switch) {
456 		pdev_name = pci_name(client->pdev);
457 		ret = vga_switchto_stage1(client);
458 		if (ret)
459 			printk(KERN_ERR "vga_switcheroo: switching failed stage 1 %d\n", ret);
460 
461 		ret = vga_switchto_stage2(client);
462 		if (ret)
463 			printk(KERN_ERR "vga_switcheroo: switching failed stage 2 %d\n", ret);
464 
465 	} else {
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;
469 
470 		ret = vga_switchto_stage1(client);
471 		if (ret)
472 			printk(KERN_ERR "vga_switcheroo: delayed switching stage 1 failed %d\n", ret);
473 	}
474 
475 out:
476 	mutex_unlock(&vgasr_mutex);
477 	return cnt;
478 }
479 
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,
484 	.read = seq_read,
485 	.llseek = seq_lseek,
486 	.release = single_release,
487 };
488 
489 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
490 {
491 	if (priv->switch_file) {
492 		debugfs_remove(priv->switch_file);
493 		priv->switch_file = NULL;
494 	}
495 	if (priv->debugfs_root) {
496 		debugfs_remove(priv->debugfs_root);
497 		priv->debugfs_root = NULL;
498 	}
499 }
500 
501 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
502 {
503 	/* already initialised */
504 	if (priv->debugfs_root)
505 		return 0;
506 	priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
507 
508 	if (!priv->debugfs_root) {
509 		printk(KERN_ERR "vga_switcheroo: Cannot create /sys/kernel/debug/vgaswitcheroo\n");
510 		goto fail;
511 	}
512 
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");
517 		goto fail;
518 	}
519 	return 0;
520 fail:
521 	vga_switcheroo_debugfs_fini(priv);
522 	return -1;
523 }
524 
525 int vga_switcheroo_process_delayed_switch(void)
526 {
527 	struct vga_switcheroo_client *client;
528 	const char *pdev_name;
529 	int ret;
530 	int err = -EINVAL;
531 
532 	mutex_lock(&vgasr_mutex);
533 	if (!vgasr_priv.delayed_switch_active)
534 		goto err;
535 
536 	printk(KERN_INFO "vga_switcheroo: processing delayed switch to %d\n", vgasr_priv.delayed_client_id);
537 
538 	client = find_client_from_id(&vgasr_priv.clients,
539 				     vgasr_priv.delayed_client_id);
540 	if (!client || !check_can_switch())
541 		goto err;
542 
543 	pdev_name = pci_name(client->pdev);
544 	ret = vga_switchto_stage2(client);
545 	if (ret)
546 		printk(KERN_ERR "vga_switcheroo: delayed switching failed stage 2 %d\n", ret);
547 
548 	vgasr_priv.delayed_switch_active = false;
549 	err = 0;
550 err:
551 	mutex_unlock(&vgasr_mutex);
552 	return err;
553 }
554 EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
555 
556