lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date:	Fri, 11 Jul 2014 20:06:15 -0400
From:	"Daniel M. Weeks" <>
To:	Jean Delvare <>, Wolfram Sang <>
Subject: [PATCH] i2c: piix4: Continue probing for auxiliary SMBus without main

Some BIOS may only allow access to the AMD auxiliary SMBus - reserving
the main SMBus for system functions only. Probing should continue even
if the main bus is not available so at least the auxiliary can be added.

Signed-off-by: Daniel M. Weeks <>
This patch may warrant some discussion. I ran across this problem on an
AMD Hudson board where the main SMBus is hard-wired for debugging but
the auxiliary bus is exposed for expansion. Either purposefully or
because the BIOS is a little broken, loading this module used to result
in an ACPI conflict for the main bus and neither was usable. With the
patch I'm able to use the auxiliary bus regardless of the conflict on
the main bus. I'm not 100% convinced it's the correct fix - someone with
more ACPI experience than me is going to need to review this.

drivers/i2c/busses/i2c-piix4.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index a6f54ba..d4bac64 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -628,14 +628,16 @@ static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		retval = piix4_setup(dev, id);
-	/* If no main SMBus found, give up */
-	if (retval < 0)
-		return retval;
-	/* Try to register main SMBus adapter, give up if we can't */
-	retval = piix4_add_adapter(dev, retval, &piix4_main_adapter);
-	if (retval < 0)
-		return retval;
+	/* If no main SMBus found, do not give up
+	 * some BIOS purposely only expose aux bus */
+	if (retval < 0) {
+		dev_info(&dev->dev, "No main SMBus; checking auxiliary\n");
+	} else {
+		/* Try to register main SMBus adapter, give up if we can't */
+		retval = piix4_add_adapter(dev, retval, &piix4_main_adapter);
+		if (retval < 0)
+			return retval;
+	}
 	/* Check for auxiliary SMBus on some AMD chipsets */
 	retval = -ENODEV;
Daniel M. Weeks

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists