diff options
author | Ingo Molnar <mingo@elte.hu> | 2008-08-25 11:10:42 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-08-25 11:10:42 +0200 |
commit | ea1c9de45ecb162841c9b4e0fa303a245d59b1c8 (patch) | |
tree | 72ef1624d8a4c581ad94a84f38f941682562030b /arch/x86/kernel/cpu/addon_cpuid_features.c | |
parent | 4e1d112cac08049e764fe3c4f6d3ec92529f9f68 (diff) | |
parent | a2bd7274b47124d2fc4dfdb8c0591f545ba749dd (diff) |
Merge branch 'x86/urgent' into x86/cleanups
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: |