panic: keep blinking in spite of long spin timer mode

To keep panic_timeout accuracy when running under a hypervisor, the
current implementation only spins on long time (1 second) calls to mdelay.
 That brings a good effect, but the problem is the keyboard LEDs don't
blink at all on that situation.

This patch changes to call to panic_blink_enter() between every mdelay and
keeps blinking in spite of long spin timer mode.

The time to call to mdelay is now 100ms.  Even this change will keep
panic_timeout accuracy enough when running under a hypervisor.

Signed-off-by: TAMUKI Shoichi <tamuki@linet.gr.jp>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 20 deletions

diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index 258b98b9d7c2..46e4ba0b9246 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -61,10 +61,6 @@ static bool i8042_noloop;
 module_param_named(noloop, i8042_noloop, bool, 0);
 MODULE_PARM_DESC(noloop, "Disable the AUX Loopback command while probing for the AUX port");
 
-static unsigned int i8042_blink_frequency = 500;
-module_param_named(panicblink, i8042_blink_frequency, uint, 0600);
-MODULE_PARM_DESC(panicblink, "Frequency with which keyboard LEDs should blink when kernel panics");
-
 #ifdef CONFIG_X86
 static bool i8042_dritek;
 module_param_named(dritek, i8042_dritek, bool, 0);
@@ -1030,8 +1026,8 @@ static void i8042_controller_reset(void)
 
 
 /*
- * i8042_panic_blink() will flash the keyboard LEDs and is called when
- * kernel panics. Flashing LEDs is useful for users running X who may
+ * i8042_panic_blink() will turn the keyboard LEDs on or off and is called
+ * when kernel panics. Flashing LEDs is useful for users running X who may
  * not see the console and will help distingushing panics from "real"
  * lockups.
  *
@@ -1041,22 +1037,12 @@ static void i8042_controller_reset(void)
 
 #define DELAY do { mdelay(1); if (++delay > 10) return delay; } while(0)
 
-static long i8042_panic_blink(long count)
+static long i8042_panic_blink(int state)
 {
 	long delay = 0;
-	static long last_blink;
-	static char led;
-
-	/*
-	 * We expect frequency to be about 1/2s. KDB uses about 1s.
-	 * Make sure they are different.
-	 */
-	if (!i8042_blink_frequency)
-		return 0;
-	if (count - last_blink < i8042_blink_frequency)
-		return 0;
+	char led;
 
-	led ^= 0x01 | 0x04;
+	led = (state) ? 0x01 | 0x04 : 0;
 	while (i8042_read_status() & I8042_STR_IBF)
 		DELAY;
 	dbg("%02x -> i8042 (panic blink)", 0xed);
@@ -1069,7 +1055,6 @@ static long i8042_panic_blink(long count)
 	dbg("%02x -> i8042 (panic blink)", led);
 	i8042_write_data(led);
 	DELAY;
-	last_blink = count;
 	return delay;
 }