i2c: i801: Restore configuration at shutdown

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>

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index fcffd60410ebd73c4e2375f34ea23fd5d0cec037..b32bf7eac3c807f1147fd8b526855fa46926bbcb 100644 (file)
--- 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 *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,
        },