diff options
| author | Ingo Molnar <mingo@elte.hu> | 2008-09-04 13:02:35 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-09-04 13:02:35 +0200 |
| commit | 42390cdec5f6e6e2ee54f308474a6ef7dd16aa5c (patch) | |
| tree | e9684c84f53272319a5acd4b9c86503f30274a51 /arch/x86/kernel/cpu/addon_cpuid_features.c | |
| parent | 11c231a962c740b3216eb6565149ae5a7944cba7 (diff) | |
| parent | d210baf53b699fc61aa891c177b71d7082d3b957 (diff) | |
Merge branch 'linus' into x86/x2apic
Conflicts:
arch/x86/kernel/cpu/cyrix.c
include/asm-x86/cpufeature.h
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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 a2d1a545767..0d9c993aa93 100644 --- a/arch/x86/kernel/cpu/addon_cpuid_features.c +++ b/arch/x86/kernel/cpu/addon_cpuid_features.c @@ -144,9 +144,22 @@ 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: |