release/5.2.41/ACPI-watchdog-Set-default-timeout-in-probe.patch

From 78e0c00e315105c45ee15d75fc0b600ba7c03529 Mon Sep 17 00:00:00 2001
From: Mika Westerberg <mika.westerberg@linux.intel.com>
Date: Wed, 12 Feb 2020 17:59:41 +0300
Subject: [PATCH] ACPI: watchdog: Set default timeout in probe

commit cabe17d0173ab04bd3f87b8199ae75f43f1ea473 upstream.

If the BIOS default timeout for the watchdog is too small userspace may
not have enough time to configure new timeout after opening the device
before the system is already reset. For this reason program default
timeout of 30 seconds in the driver probe and allow userspace to change
this from command line or through module parameter (wdat_wdt.timeout).

Reported-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/watchdog/wdat_wdt.c b/drivers/watchdog/wdat_wdt.c
index 1ce39de917f0..88c5e6361aa0 100644
--- a/drivers/watchdog/wdat_wdt.c
+++ b/drivers/watchdog/wdat_wdt.c
@@ -54,6 +54,13 @@ module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 
+#define WDAT_DEFAULT_TIMEOUT	30
+
+static int timeout = WDAT_DEFAULT_TIMEOUT;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
+		 __MODULE_STRING(WDAT_DEFAULT_TIMEOUT) ")");
+
 static int wdat_wdt_read(struct wdat_wdt *wdat,
 	 const struct wdat_instruction *instr, u32 *value)
 {
@@ -438,6 +445,22 @@ static int wdat_wdt_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, wdat);
 
+	/*
+	 * Set initial timeout so that userspace has time to configure the
+	 * watchdog properly after it has opened the device. In some cases
+	 * the BIOS default is too short and causes immediate reboot.
+	 */
+	if (timeout * 1000 < wdat->wdd.min_hw_heartbeat_ms ||
+	    timeout * 1000 > wdat->wdd.max_hw_heartbeat_ms) {
+		dev_warn(dev, "Invalid timeout %d given, using %d\n",
+			 timeout, WDAT_DEFAULT_TIMEOUT);
+		timeout = WDAT_DEFAULT_TIMEOUT;
+	}
+
+	ret = wdat_wdt_set_timeout(&wdat->wdd, timeout);
+	if (ret)
+		return ret;
+
 	watchdog_set_nowayout(&wdat->wdd, nowayout);
 	return devm_watchdog_register_device(dev, &wdat->wdd);
 }
-- 
2.7.4