diff options
| author | H. Peter Anvin <hpa@zytor.com> | 2008-09-04 08:08:42 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2008-09-04 08:08:42 -0700 |
| commit | 7203781c98ad9147564d327de6f6513ad8fc0f4e (patch) | |
| tree | 5c29a2a04a626bf08a0d56fd8a0068b3c92ad284 /arch/x86/kernel/cpu/addon_cpuid_features.c | |
| parent | 671eef85a3e885dff4ce210d8774ad50a91d5967 (diff) | |
| parent | af2e1f276ff08f17192411ea3b71c13a758dfe12 (diff) | |
Merge branch 'x86/cpu' into x86/core
Conflicts:
arch/x86/kernel/cpu/feature_names.c
include/asm-x86/cpufeature.h
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: |