linux-kernel - [015/140] hwmon: (k10temp) Do not blacklist known working CPU models

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Message-Id: <20100730173104.142298489@clark.site>
Date:	Fri, 30 Jul 2010 10:29:40 -0700
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Jean Delvare <khali@...ux-fr.org>,
	Clemens Ladisch <clemens@...isch.de>,
	Andreas Herrmann <andreas.herrmann3@....com>
Subject: [015/140] hwmon: (k10temp) Do not blacklist known working CPU models

2.6.33-stable review patch.  If anyone has any objections, please let us know.

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

From: Jean Delvare <khali@...ux-fr.org>

commit eefc2d9e3d4f8820f2c128a0e44a23de28b1ed64 upstream.

When detecting AM2+ or AM3 socket with DDR2, only blacklist cores
which are known to exist in AM2+ format.

Signed-off-by: Jean Delvare <khali@...ux-fr.org>
Acked-by: Clemens Ladisch <clemens@...isch.de>
Cc: Andreas Herrmann <andreas.herrmann3@....com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 drivers/hwmon/k10temp.c |   14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

--- a/drivers/hwmon/k10temp.c
+++ b/drivers/hwmon/k10temp.c
@@ -112,11 +112,21 @@ static bool __devinit has_erratum_319(st
 	if (pkg_type != CPUID_PKGTYPE_AM2R2_AM3)
 		return false;
 
-	/* Differentiate between AM2+ (bad) and AM3 (good) */
+	/* DDR3 memory implies socket AM3, which is good */
 	pci_bus_read_config_dword(pdev->bus,
 				  PCI_DEVFN(PCI_SLOT(pdev->devfn), 2),
 				  REG_DCT0_CONFIG_HIGH, &reg_dram_cfg);
-	return !(reg_dram_cfg & DDR3_MODE);
+	if (reg_dram_cfg & DDR3_MODE)
+		return false;
+
+	/*
+	 * Unfortunately it is possible to run a socket AM3 CPU with DDR2
+	 * memory. We blacklist all the cores which do exist in socket AM2+
+	 * format. It still isn't perfect, as RB-C2 cores exist in both AM2+
+	 * and AM3 formats, but that's the best we can do.
+	 */
+	return boot_cpu_data.x86_model < 4 ||
+	       (boot_cpu_data.x86_model == 4 && boot_cpu_data.x86_mask <= 2);
 }
 
 static int __devinit k10temp_probe(struct pci_dev *pdev,


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