diff options
author | David Woodhouse <David.Woodhouse@intel.com> | 2008-09-01 11:32:13 +0100 |
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committer | David Woodhouse <David.Woodhouse@intel.com> | 2008-09-01 11:32:13 +0100 |
commit | 9d7548d4ca3c52ecb58f098a32b0756cdf8f96ee (patch) | |
tree | 651f7058bbaa2d8b2855286380d614afcf505118 /arch/x86/kernel/cpu/addon_cpuid_features.c | |
parent | 31db6e9ea1dbdcf66b8227b4f7035dee1b1dd8c0 (diff) | |
parent | bef69ea0dcce574a425feb0a5aa4c63dd108b9a6 (diff) |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Diffstat (limited to 'arch/x86/kernel/cpu/addon_cpuid_features.c')
-rw-r--r-- | arch/x86/kernel/cpu/addon_cpuid_features.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/addon_cpuid_features.c b/arch/x86/kernel/cpu/addon_cpuid_features.c index 84a8220a607..a6ef672adbb 100644 --- a/arch/x86/kernel/cpu/addon_cpuid_features.c +++ b/arch/x86/kernel/cpu/addon_cpuid_features.c @@ -56,9 +56,22 @@ void __cpuinit validate_pat_support(struct cpuinfo_x86 *c) switch (c->x86_vendor) { case X86_VENDOR_INTEL: - if (c->x86 == 0xF || (c->x86 == 6 && c->x86_model >= 15)) + /* + * There is a known erratum on Pentium III and Core Solo + * and Core Duo CPUs. + * " Page with PAT set to WC while associated MTRR is UC + * may consolidate to UC " + * Because of this erratum, it is better to stick with + * setting WC in MTRR rather than using PAT on these CPUs. + * + * Enable PAT WC only on P4, Core 2 or later CPUs. + */ + if (c->x86 > 0x6 || (c->x86 == 6 && c->x86_model >= 15)) return; - break; + + pat_disable("PAT WC disabled due to known CPU erratum."); + return; + case X86_VENDOR_AMD: case X86_VENDOR_CENTAUR: case X86_VENDOR_TRANSMETA: |