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[PATCH] Console blanking locking fix

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I've had WARN_CONSOLE_UNLOCKED warnings when calling TIOCLINUX
TIOCL_BLANKSCREEN and TIOCL_UNBLANKSCREEN.

(I'm blind and I use a braille display.  I use those functions to blank my
laptop's screen so people don't read it, and hopefully to conserve power.)

The warnings are from these places:
do_blank_screen at drivers/char/vt.c:2754 (Not tainted)
save_screen at drivers/char/vt.c:575 (Not tainted)
do_unblank_screen at drivers/char/vt.c:2822 (Not tainted)
set_palette at drivers/char/vt.c:2908 (Not tainted)

At a glance I would think the following patch ought to fix that.  Tested on
one machine.  Could you please tell me if this is correct and/or forward
the patch where appropriate...

Signed-off-by: Stephane Doyon <s.doyon@videotron.ca>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Stephane Doyon 2005-09-06 15:17:31 -07:00 committed by Linus Torvalds
parent f62c6d0a26
commit 2d237c6365
1 changed files with 4 additions and 0 deletions
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4
drivers/char/vt.c
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@ -2272,7 +2272,9 @@ int tioclinux(struct tty_struct *tty, unsigned long arg)
ret = paste_selection(tty);
break;
case TIOCL_UNBLANKSCREEN:
acquire_console_sem();
unblank_screen();
release_console_sem();
break;
case TIOCL_SELLOADLUT:
ret = sel_loadlut(p);
@ -2317,8 +2319,10 @@ int tioclinux(struct tty_struct *tty, unsigned long arg)
}
break;
case TIOCL_BLANKSCREEN: /* until explicitly unblanked, not only poked */
acquire_console_sem();
ignore_poke = 1;
do_blank_screen(0);
release_console_sem();
break;
case TIOCL_BLANKEDSCREEN:
ret = console_blanked;