From: Lee Revell Enable write combining for server works LE rev > 6 per http://www.ussg.iu.edu/hypermail/linux/kernel/0104.3/1007.html Signed-Off-By: Lee Revell Signed-off-by: Andrew Morton --- arch/i386/kernel/cpu/mtrr/main.c | 14 +++++++++----- 1 files changed, 9 insertions(+), 5 deletions(-) diff -puN arch/i386/kernel/cpu/mtrr/main.c~enable-write-combining-for-server-works-le-rev-6 arch/i386/kernel/cpu/mtrr/main.c --- 25/arch/i386/kernel/cpu/mtrr/main.c~enable-write-combining-for-server-works-le-rev-6 2005-04-25 18:47:08.006161568 -0700 +++ 25-akpm/arch/i386/kernel/cpu/mtrr/main.c 2005-04-25 18:47:25.208546408 -0700 @@ -72,17 +72,21 @@ void set_mtrr_ops(struct mtrr_ops * ops) static int have_wrcomb(void) { struct pci_dev *dev; + u8 rev; if ((dev = pci_get_class(PCI_CLASS_BRIDGE_HOST << 8, NULL)) != NULL) { - /* ServerWorks LE chipsets have problems with write-combining + /* ServerWorks LE chipsets < rev 6 have problems with write-combining Don't allow it and leave room for other chipsets to be tagged */ if (dev->vendor == PCI_VENDOR_ID_SERVERWORKS && dev->device == PCI_DEVICE_ID_SERVERWORKS_LE) { - printk(KERN_INFO "mtrr: Serverworks LE detected. Write-combining disabled.\n"); - pci_dev_put(dev); - return 0; + pci_read_config_byte(dev, PCI_CLASS_REVISION, &rev); + if (rev <= 5) { + printk(KERN_INFO "mtrr: Serverworks LE rev < 6 detected. Write-combining disabled.\n"); + pci_dev_put(dev); + return 0; + } } - /* Intel 450NX errata # 23. Non ascending cachline evictions to + /* Intel 450NX errata # 23. Non ascending cacheline evictions to write combining memory may resulting in data corruption */ if (dev->vendor == PCI_VENDOR_ID_INTEL && dev->device == PCI_DEVICE_ID_INTEL_82451NX) { _