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56e6c104e4
The macro WARN_CONSOLE_UNLOCKED prints a warning when a thread enters the console's critical section without having acquired the console lock. The console lock can be ignored when debugging the console using printk, but this makes WARN_CONSOLE_UNLOCKED generate unnecessary warnings. The variable ignore_console_lock_warning temporarily disables WARN_CONSOLE_UNLOCKED. Developers interested in debugging the console's critical sections should increment it before entering the CS and decrement it after leaving the CS. Setting ignore_console_lock_warning is only for debugging. Regular operation should not manipulate it. Acknoledgements: This patch is based on an earlier version by Steven Rostedt. The use of atomic increment/decrement was suggested by Petr Mladek. Link: http://lkml.kernel.org/r/717e6337-e7a6-7a92-1c1b-8929a25696b5@suse.de Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Acked-by: Hans de Goede <hdegoede@redhat.com> Acked-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> [b.zolnierkie: use <linux/atomic.h>] Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
232 lines
7.3 KiB
C
232 lines
7.3 KiB
C
/*
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* linux/include/linux/console.h
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*
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* Copyright (C) 1993 Hamish Macdonald
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file COPYING in the main directory of this archive
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* for more details.
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*
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* Changed:
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* 10-Mar-94: Arno Griffioen: Conversion for vt100 emulator port from PC LINUX
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*/
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#ifndef _LINUX_CONSOLE_H_
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#define _LINUX_CONSOLE_H_ 1
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#include <linux/atomic.h>
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#include <linux/types.h>
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struct vc_data;
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struct console_font_op;
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struct console_font;
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struct module;
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struct tty_struct;
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struct notifier_block;
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/*
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* this is what the terminal answers to a ESC-Z or csi0c query.
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*/
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#define VT100ID "\033[?1;2c"
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#define VT102ID "\033[?6c"
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enum con_scroll {
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SM_UP,
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SM_DOWN,
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};
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/**
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* struct consw - callbacks for consoles
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*
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* @con_scroll: move lines from @top to @bottom in direction @dir by @lines.
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* Return true if no generic handling should be done.
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* Invoked by csi_M and printing to the console.
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* @con_set_palette: sets the palette of the console to @table (optional)
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* @con_scrolldelta: the contents of the console should be scrolled by @lines.
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* Invoked by user. (optional)
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*/
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struct consw {
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struct module *owner;
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const char *(*con_startup)(void);
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void (*con_init)(struct vc_data *vc, int init);
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void (*con_deinit)(struct vc_data *vc);
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void (*con_clear)(struct vc_data *vc, int sy, int sx, int height,
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int width);
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void (*con_putc)(struct vc_data *vc, int c, int ypos, int xpos);
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void (*con_putcs)(struct vc_data *vc, const unsigned short *s,
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int count, int ypos, int xpos);
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void (*con_cursor)(struct vc_data *vc, int mode);
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bool (*con_scroll)(struct vc_data *vc, unsigned int top,
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unsigned int bottom, enum con_scroll dir,
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unsigned int lines);
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int (*con_switch)(struct vc_data *vc);
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int (*con_blank)(struct vc_data *vc, int blank, int mode_switch);
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int (*con_font_set)(struct vc_data *vc, struct console_font *font,
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unsigned int flags);
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int (*con_font_get)(struct vc_data *vc, struct console_font *font);
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int (*con_font_default)(struct vc_data *vc,
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struct console_font *font, char *name);
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int (*con_font_copy)(struct vc_data *vc, int con);
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int (*con_resize)(struct vc_data *vc, unsigned int width,
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unsigned int height, unsigned int user);
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void (*con_set_palette)(struct vc_data *vc,
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const unsigned char *table);
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void (*con_scrolldelta)(struct vc_data *vc, int lines);
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int (*con_set_origin)(struct vc_data *vc);
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void (*con_save_screen)(struct vc_data *vc);
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u8 (*con_build_attr)(struct vc_data *vc, u8 color, u8 intensity,
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u8 blink, u8 underline, u8 reverse, u8 italic);
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void (*con_invert_region)(struct vc_data *vc, u16 *p, int count);
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u16 *(*con_screen_pos)(struct vc_data *vc, int offset);
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unsigned long (*con_getxy)(struct vc_data *vc, unsigned long position,
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int *px, int *py);
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/*
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* Flush the video console driver's scrollback buffer
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*/
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void (*con_flush_scrollback)(struct vc_data *vc);
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/*
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* Prepare the console for the debugger. This includes, but is not
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* limited to, unblanking the console, loading an appropriate
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* palette, and allowing debugger generated output.
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*/
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int (*con_debug_enter)(struct vc_data *vc);
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/*
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* Restore the console to its pre-debug state as closely as possible.
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*/
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int (*con_debug_leave)(struct vc_data *vc);
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};
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extern const struct consw *conswitchp;
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extern const struct consw dummy_con; /* dummy console buffer */
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extern const struct consw vga_con; /* VGA text console */
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extern const struct consw newport_con; /* SGI Newport console */
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extern const struct consw prom_con; /* SPARC PROM console */
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int con_is_bound(const struct consw *csw);
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int do_unregister_con_driver(const struct consw *csw);
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int do_take_over_console(const struct consw *sw, int first, int last, int deflt);
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void give_up_console(const struct consw *sw);
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#ifdef CONFIG_HW_CONSOLE
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int con_debug_enter(struct vc_data *vc);
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int con_debug_leave(void);
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#else
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static inline int con_debug_enter(struct vc_data *vc)
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{
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return 0;
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}
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static inline int con_debug_leave(void)
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{
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return 0;
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}
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#endif
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/* cursor */
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#define CM_DRAW (1)
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#define CM_ERASE (2)
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#define CM_MOVE (3)
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/*
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* The interface for a console, or any other device that wants to capture
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* console messages (printer driver?)
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*
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* If a console driver is marked CON_BOOT then it will be auto-unregistered
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* when the first real console is registered. This is for early-printk drivers.
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*/
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#define CON_PRINTBUFFER (1)
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#define CON_CONSDEV (2) /* Last on the command line */
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#define CON_ENABLED (4)
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#define CON_BOOT (8)
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#define CON_ANYTIME (16) /* Safe to call when cpu is offline */
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#define CON_BRL (32) /* Used for a braille device */
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#define CON_EXTENDED (64) /* Use the extended output format a la /dev/kmsg */
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struct console {
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char name[16];
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void (*write)(struct console *, const char *, unsigned);
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int (*read)(struct console *, char *, unsigned);
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struct tty_driver *(*device)(struct console *, int *);
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void (*unblank)(void);
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int (*setup)(struct console *, char *);
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int (*match)(struct console *, char *name, int idx, char *options);
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short flags;
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short index;
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int cflag;
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void *data;
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struct console *next;
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};
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/*
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* for_each_console() allows you to iterate on each console
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*/
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#define for_each_console(con) \
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for (con = console_drivers; con != NULL; con = con->next)
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extern int console_set_on_cmdline;
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extern struct console *early_console;
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extern int add_preferred_console(char *name, int idx, char *options);
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extern void register_console(struct console *);
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extern int unregister_console(struct console *);
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extern struct console *console_drivers;
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extern void console_lock(void);
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extern int console_trylock(void);
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extern void console_unlock(void);
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extern void console_conditional_schedule(void);
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extern void console_unblank(void);
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extern void console_flush_on_panic(void);
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extern struct tty_driver *console_device(int *);
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extern void console_stop(struct console *);
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extern void console_start(struct console *);
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extern int is_console_locked(void);
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extern int braille_register_console(struct console *, int index,
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char *console_options, char *braille_options);
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extern int braille_unregister_console(struct console *);
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#ifdef CONFIG_TTY
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extern void console_sysfs_notify(void);
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#else
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static inline void console_sysfs_notify(void)
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{ }
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#endif
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extern bool console_suspend_enabled;
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/* Suspend and resume console messages over PM events */
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extern void suspend_console(void);
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extern void resume_console(void);
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int mda_console_init(void);
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void prom_con_init(void);
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void vcs_make_sysfs(int index);
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void vcs_remove_sysfs(int index);
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/* Some debug stub to catch some of the obvious races in the VT code */
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#define WARN_CONSOLE_UNLOCKED() \
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WARN_ON(!atomic_read(&ignore_console_lock_warning) && \
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!is_console_locked() && !oops_in_progress)
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/*
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* Increment ignore_console_lock_warning if you need to quiet
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* WARN_CONSOLE_UNLOCKED() for debugging purposes.
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*/
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extern atomic_t ignore_console_lock_warning;
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/* VESA Blanking Levels */
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#define VESA_NO_BLANKING 0
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#define VESA_VSYNC_SUSPEND 1
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#define VESA_HSYNC_SUSPEND 2
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#define VESA_POWERDOWN 3
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#ifdef CONFIG_VGA_CONSOLE
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extern bool vgacon_text_force(void);
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#else
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static inline bool vgacon_text_force(void) { return false; }
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#endif
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extern void console_init(void);
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/* For deferred console takeover */
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void dummycon_register_output_notifier(struct notifier_block *nb);
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void dummycon_unregister_output_notifier(struct notifier_block *nb);
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#endif /* _LINUX_CONSOLE_H */
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