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Commit d2be8ee5 authored by Fredrik Roubert's avatar Fredrik Roubert Committed by Linus Torvalds
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[PATCH] fix magic sysrq on strange keyboards 



Magic sysrq fails to work on many keyboards, particulary most of notebook
keyboards.  This patch fixes it.

The idea is quite simple: Discard the SysRq break code if Alt is still being
held down.  This way the broken keyboard can send the break code (or the user
with a normal keyboard can release the SysRq key) and the kernel waits until
the next key is pressed or the Alt key is released.

Signed-off-by: default avatarPavel Machek <pavel@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0c6856f7

drivers/char/keyboard.c

+8 −2
Original line number Diff line number Diff line
@@ -151,6 +151,7 @@ unsigned char kbd_sysrq_xlate[KEY_MAX + 1] = 
        "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */

        "\r\000/";                                      /* 0x60 - 0x6f */

static int sysrq_down;

static int sysrq_alt_use;

#endif

static int sysrq_alt;
@@ -1143,7 +1144,7 @@ static void kbd_keycode(unsigned int keycode, int down, 
	kbd = kbd_table + fg_console;



	if (keycode == KEY_LEFTALT || keycode == KEY_RIGHTALT)

		sysrq_alt = down;

		sysrq_alt = down ? keycode : 0;

#ifdef CONFIG_SPARC

	if (keycode == KEY_STOP)

		sparc_l1_a_state = down;
@@ -1163,9 +1164,14 @@ static void kbd_keycode(unsigned int keycode, int down, 


#ifdef CONFIG_MAGIC_SYSRQ	       /* Handle the SysRq Hack */

	if (keycode == KEY_SYSRQ && (sysrq_down || (down == 1 && sysrq_alt))) {

		if (!sysrq_down) {

			sysrq_down = down;

			sysrq_alt_use = sysrq_alt;

		}

		return;

	}

	if (sysrq_down && !down && keycode == sysrq_alt_use)

		sysrq_down = 0;

	if (sysrq_down && down && !rep) {

		handle_sysrq(kbd_sysrq_xlate[keycode], regs, tty);

		return;