From f7f6d915a10f7f2bce17e3b1b7d3376562395a28 Mon Sep 17 00:00:00 2001
From: Jean Delvare <jdelvare@suse.de>
Date: Wed, 11 Apr 2018 18:05:34 +0200
Subject: [PATCH] i2c: i801: Restore configuration at shutdown
Git-commit: f7f6d915a10f7f2bce17e3b1b7d3376562395a28
Patch-mainline: v4.17-rc1
References: bsc#1051510

On some systems, the BIOS expects certain SMBus register values to
match the hardware defaults. Restore these configuration registers at
shutdown time to avoid confusing the BIOS. This avoids hard-locking
such systems upon reboot.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Tested-by: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@vger.kernel.org
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/i2c/busses/i2c-i801.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -1696,6 +1696,15 @@ static void i801_remove(struct pci_dev *
 	 */
 }
 
+static void i801_shutdown(struct pci_dev *dev)
+{
+	struct i801_priv *priv = pci_get_drvdata(dev);
+
+	/* Restore config registers to avoid hard hang on some systems */
+	i801_disable_host_notify(priv);
+	pci_write_config_byte(dev, SMBHSTCFG, priv->original_hstcfg);
+}
+
 #ifdef CONFIG_PM
 static int i801_suspend(struct device *dev)
 {
@@ -1725,6 +1734,7 @@ static struct pci_driver i801_driver = {
 	.id_table	= i801_ids,
 	.probe		= i801_probe,
 	.remove		= i801_remove,
+	.shutdown	= i801_shutdown,
 	.driver		= {
 		.pm	= &i801_pm_ops,
 	},