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Commit 0bcd0b6a authored by Marc van der Wal's avatar Marc van der Wal Committed by Wim Van Sebroeck
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watchdog: it87_wdt: Work around non-working CIR interrupts 

On some hardware platforms, the it87_wdt watchdog resets the machine
despite the watchdog daemon running and writing to /dev/watchdog.

This is due to Consumer IR buffer underrun interrupts being used as
triggers to reset the timer.  On some buggy hardware implementations
such as the iEi AFL-12A-N270 single-board computer, this method does
not work.

However, resetting the timer by writing its original timeout value in
its configuration register over and over again suppresses the unwanted
reboots.

Add a module option (nocir), 0 by default in order not to break existing
setups.  Setting it to 1 enables the workaround.

Fixes bug #42801 <https://bugzilla.kernel.org/show_bug.cgi?id=42801

>.
Tested primarily on Linux 3.5.7, applies cleanly on Linux 3.13.5.

Signed-off-by: default avatarMarc van der Wal <x0r+kernel@x0r.fr>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
parent 5e82ec94

Documentation/watchdog/watchdog-parameters.txt

+2 −0
Original line number Diff line number Diff line
@@ -150,6 +150,8 @@ nowayout: Disable watchdog shutdown on close 
-------------------------------------------------

it87_wdt:

nogameport: Forbid the activation of game port, default=0

nocir: Forbid the use of CIR (workaround for some buggy setups); set to 1 if

system resets despite watchdog daemon running, default=0

exclusive: Watchdog exclusive device open, default=1

timeout: Watchdog timeout in seconds, default=60

testmode: Watchdog test mode (1 = no reboot), default=0

drivers/watchdog/it87_wdt.c

+31 −10
Original line number Diff line number Diff line
@@ -54,6 +54,7 @@ 


/* Defaults for Module Parameter */

#define DEFAULT_NOGAMEPORT	0

#define DEFAULT_NOCIR		0

#define DEFAULT_EXCLUSIVE	1

#define DEFAULT_TIMEOUT		60

#define DEFAULT_TESTMODE	0
@@ -136,11 +137,13 @@ 
#define WDTS_LOCKED	3

#define WDTS_USE_GP	4

#define WDTS_EXPECTED	5

#define WDTS_USE_CIR	6



static	unsigned int base, gpact, ciract, max_units, chip_type;

static	unsigned long wdt_status;



static	int nogameport = DEFAULT_NOGAMEPORT;

static int nocir      = DEFAULT_NOCIR;

static	int exclusive  = DEFAULT_EXCLUSIVE;

static	int timeout    = DEFAULT_TIMEOUT;

static	int testmode   = DEFAULT_TESTMODE;
@@ -149,6 +152,9 @@ static bool nowayout = DEFAULT_NOWAYOUT; 
module_param(nogameport, int, 0);

MODULE_PARM_DESC(nogameport, "Forbid the activation of game port, default="

		__MODULE_STRING(DEFAULT_NOGAMEPORT));

module_param(nocir, int, 0);

MODULE_PARM_DESC(nocir, "Forbid the use of Consumer IR interrupts to reset timer, default="

		__MODULE_STRING(DEFAULT_NOCIR));

module_param(exclusive, int, 0);

MODULE_PARM_DESC(exclusive, "Watchdog exclusive device open, default="

		__MODULE_STRING(DEFAULT_EXCLUSIVE));
@@ -258,9 +264,17 @@ static void wdt_keepalive(void) 
{

	if (test_bit(WDTS_USE_GP, &wdt_status))

		inb(base);

	else

	else if (test_bit(WDTS_USE_CIR, &wdt_status))

		/* The timer reloads with around 5 msec delay */

		outb(0x55, CIR_DR(base));

	else {

		if (superio_enter())

			return;



		superio_select(GPIO);

		wdt_update_timeout();

		superio_exit();

	}

	set_bit(WDTS_KEEPALIVE, &wdt_status);

}
@@ -273,7 +287,7 @@ static int wdt_start(void) 
	superio_select(GPIO);

	if (test_bit(WDTS_USE_GP, &wdt_status))

		superio_outb(WDT_GAMEPORT, WDTCTRL);

	else

	else if (test_bit(WDTS_USE_CIR, &wdt_status))

		superio_outb(WDT_CIRINT, WDTCTRL);

	wdt_update_timeout();
@@ -660,7 +674,7 @@ static int __init it87_wdt_init(void) 
	}



	/* If we haven't Gameport support, try to get CIR support */

	if (!test_bit(WDTS_USE_GP, &wdt_status)) {

	if (!nocir && !test_bit(WDTS_USE_GP, &wdt_status)) {

		if (!request_region(CIR_BASE, 8, WATCHDOG_NAME)) {

			if (gp_rreq_fail)

				pr_err("I/O Address 0x%04x and 0x%04x already in use\n",
@@ -682,6 +696,7 @@ static int __init it87_wdt_init(void) 
			superio_select(GAMEPORT);

			superio_outb(gpact, ACTREG);

		}

		set_bit(WDTS_USE_CIR, &wdt_status);

	}



	if (timeout < 1 || timeout > max_units * 60) {
@@ -707,7 +722,7 @@ static int __init it87_wdt_init(void) 
	}



	/* Initialize CIR to use it as keepalive source */

	if (!test_bit(WDTS_USE_GP, &wdt_status)) {

	if (test_bit(WDTS_USE_CIR, &wdt_status)) {

		outb(0x00, CIR_RCR(base));

		outb(0xc0, CIR_TCR1(base));

		outb(0x5c, CIR_TCR2(base));
@@ -717,9 +732,9 @@ static int __init it87_wdt_init(void) 
		outb(0x09, CIR_IER(base));

	}



	pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d exclusive=%d nogameport=%d)\n",

	pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d exclusive=%d nogameport=%d nocir=%d)\n",

		chip_type, chip_rev, timeout,

		nowayout, testmode, exclusive, nogameport);

		nowayout, testmode, exclusive, nogameport, nocir);



	superio_exit();

	return 0;
@@ -727,8 +742,10 @@ static int __init it87_wdt_init(void) 
err_out_reboot:

	unregister_reboot_notifier(&wdt_notifier);

err_out_region:

	release_region(base, test_bit(WDTS_USE_GP, &wdt_status) ? 1 : 8);

	if (!test_bit(WDTS_USE_GP, &wdt_status)) {

	if (test_bit(WDTS_USE_GP, &wdt_status))

		release_region(base, 1);

	else if (test_bit(WDTS_USE_CIR, &wdt_status)) {

		release_region(base, 8);

		superio_select(CIR);

		superio_outb(ciract, ACTREG);

	}
@@ -754,7 +771,7 @@ static void __exit it87_wdt_exit(void) 
		if (test_bit(WDTS_USE_GP, &wdt_status)) {

			superio_select(GAMEPORT);

			superio_outb(gpact, ACTREG);

		} else {

		} else if (test_bit(WDTS_USE_CIR, &wdt_status)) {

			superio_select(CIR);

			superio_outb(ciract, ACTREG);

		}
@@ -763,7 +780,11 @@ static void __exit it87_wdt_exit(void) 


	misc_deregister(&wdt_miscdev);

	unregister_reboot_notifier(&wdt_notifier);

	release_region(base, test_bit(WDTS_USE_GP, &wdt_status) ? 1 : 8);



	if (test_bit(WDTS_USE_GP, &wdt_status))

		release_region(base, 1);

	else if (test_bit(WDTS_USE_CIR, &wdt_status))

		release_region(base, 8);

}



module_init(it87_wdt_init);