Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
37cce26b | 2 | * Functions for saving/restoring console. |
1da177e4 LT |
3 | * |
4 | * Originally from swsusp. | |
5 | */ | |
6 | ||
f43f627d | 7 | #include <linux/console.h> |
1da177e4 LT |
8 | #include <linux/vt_kern.h> |
9 | #include <linux/kbd_kern.h> | |
5ada918b | 10 | #include <linux/vt.h> |
b6f448e9 | 11 | #include <linux/module.h> |
1ff6bbfd | 12 | #include <linux/slab.h> |
1da177e4 LT |
13 | #include "power.h" |
14 | ||
46cd2f32 RW |
15 | #define SUSPEND_CONSOLE (MAX_NR_CONSOLES-1) |
16 | ||
1da177e4 | 17 | static int orig_fgconsole, orig_kmsg; |
1da177e4 | 18 | |
f43f627d JB |
19 | static DEFINE_MUTEX(vt_switch_mutex); |
20 | ||
21 | struct pm_vt_switch { | |
22 | struct list_head head; | |
23 | struct device *dev; | |
24 | bool required; | |
25 | }; | |
26 | ||
27 | static LIST_HEAD(pm_vt_switch_list); | |
28 | ||
29 | ||
30 | /** | |
31 | * pm_vt_switch_required - indicate VT switch at suspend requirements | |
32 | * @dev: device | |
33 | * @required: if true, caller needs VT switch at suspend/resume time | |
34 | * | |
35 | * The different console drivers may or may not require VT switches across | |
36 | * suspend/resume, depending on how they handle restoring video state and | |
37 | * what may be running. | |
38 | * | |
39 | * Drivers can indicate support for switchless suspend/resume, which can | |
40 | * save time and flicker, by using this routine and passing 'false' as | |
41 | * the argument. If any loaded driver needs VT switching, or the | |
42 | * no_console_suspend argument has been passed on the command line, VT | |
43 | * switches will occur. | |
44 | */ | |
45 | void pm_vt_switch_required(struct device *dev, bool required) | |
46 | { | |
47 | struct pm_vt_switch *entry, *tmp; | |
48 | ||
49 | mutex_lock(&vt_switch_mutex); | |
50 | list_for_each_entry(tmp, &pm_vt_switch_list, head) { | |
51 | if (tmp->dev == dev) { | |
52 | /* already registered, update requirement */ | |
53 | tmp->required = required; | |
54 | goto out; | |
55 | } | |
56 | } | |
57 | ||
58 | entry = kmalloc(sizeof(*entry), GFP_KERNEL); | |
59 | if (!entry) | |
60 | goto out; | |
61 | ||
62 | entry->required = required; | |
63 | entry->dev = dev; | |
64 | ||
65 | list_add(&entry->head, &pm_vt_switch_list); | |
66 | out: | |
67 | mutex_unlock(&vt_switch_mutex); | |
68 | } | |
69 | EXPORT_SYMBOL(pm_vt_switch_required); | |
70 | ||
71 | /** | |
72 | * pm_vt_switch_unregister - stop tracking a device's VT switching needs | |
73 | * @dev: device | |
74 | * | |
75 | * Remove @dev from the vt switch list. | |
76 | */ | |
77 | void pm_vt_switch_unregister(struct device *dev) | |
78 | { | |
79 | struct pm_vt_switch *tmp; | |
80 | ||
81 | mutex_lock(&vt_switch_mutex); | |
82 | list_for_each_entry(tmp, &pm_vt_switch_list, head) { | |
83 | if (tmp->dev == dev) { | |
84 | list_del(&tmp->head); | |
c6068504 | 85 | kfree(tmp); |
f43f627d JB |
86 | break; |
87 | } | |
88 | } | |
89 | mutex_unlock(&vt_switch_mutex); | |
90 | } | |
91 | EXPORT_SYMBOL(pm_vt_switch_unregister); | |
92 | ||
93 | /* | |
94 | * There are three cases when a VT switch on suspend/resume are required: | |
95 | * 1) no driver has indicated a requirement one way or another, so preserve | |
96 | * the old behavior | |
97 | * 2) console suspend is disabled, we want to see debug messages across | |
98 | * suspend/resume | |
99 | * 3) any registered driver indicates it needs a VT switch | |
100 | * | |
101 | * If none of these conditions is present, meaning we have at least one driver | |
102 | * that doesn't need the switch, and none that do, we can avoid it to make | |
103 | * resume look a little prettier (and suspend too, but that's usually hidden, | |
104 | * e.g. when closing the lid on a laptop). | |
105 | */ | |
106 | static bool pm_vt_switch(void) | |
107 | { | |
108 | struct pm_vt_switch *entry; | |
109 | bool ret = true; | |
110 | ||
111 | mutex_lock(&vt_switch_mutex); | |
112 | if (list_empty(&pm_vt_switch_list)) | |
113 | goto out; | |
114 | ||
115 | if (!console_suspend_enabled) | |
116 | goto out; | |
117 | ||
118 | list_for_each_entry(entry, &pm_vt_switch_list, head) { | |
119 | if (entry->required) | |
120 | goto out; | |
121 | } | |
122 | ||
123 | ret = false; | |
124 | out: | |
125 | mutex_unlock(&vt_switch_mutex); | |
126 | return ret; | |
127 | } | |
128 | ||
1da177e4 LT |
129 | int pm_prepare_console(void) |
130 | { | |
f43f627d JB |
131 | if (!pm_vt_switch()) |
132 | return 0; | |
133 | ||
8d233558 AC |
134 | orig_fgconsole = vt_move_to_console(SUSPEND_CONSOLE, 1); |
135 | if (orig_fgconsole < 0) | |
1da177e4 | 136 | return 1; |
1da177e4 | 137 | |
5ada918b | 138 | orig_kmsg = vt_kmsg_redirect(SUSPEND_CONSOLE); |
1da177e4 LT |
139 | return 0; |
140 | } | |
141 | ||
142 | void pm_restore_console(void) | |
143 | { | |
f43f627d JB |
144 | if (!pm_vt_switch()) |
145 | return; | |
146 | ||
8d233558 AC |
147 | if (orig_fgconsole >= 0) { |
148 | vt_move_to_console(orig_fgconsole, 0); | |
5ada918b | 149 | vt_kmsg_redirect(orig_kmsg); |
b090f9fa | 150 | } |
1da177e4 | 151 | } |