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