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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jean Delvare <jdelvare@suse.de>,
        Jason Andryuk <jandryuk@gmail.com>,
        Wolfram Sang <wsa@the-dreams.de>
Subject: [PATCH 4.9 07/74] i2c: i801: Restore configuration at shutdown
Date:   Fri, 27 Apr 2018 15:57:57 +0200
Message-Id: <20180427135710.201572728@linuxfoundation.org>
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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jean Delvare <jdelvare@suse.de>

commit f7f6d915a10f7f2bce17e3b1b7d3376562395a28 upstream.

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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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)
 {
@@ -1728,6 +1737,7 @@ static struct pci_driver i801_driver = {
 	.id_table	= i801_ids,
 	.probe		= i801_probe,
 	.remove		= i801_remove,
+	.shutdown	= i801_shutdown,
 	.driver		= {
 		.pm	= &i801_pm_ops,
 	},