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Subject[PATCH] x86: amd k6-2 mtrr not detected fix
From: Krzysztof Helt <krzysztof.h1@wp.pl>

The AMD K6-2 cpus have 2 mtrr registers
which are not detected by the latest Linux
kernel.
The mtrr capability is not reported through
the cpuid on these cpus. This fools early
detection function [mtrr_bp_init()] as the
mtrr capability bit is set later in
the init_amd() function.
Fix it by setting the K6 mtrr capability bit
just before the check in mtrr_bp_init().
The added condition is copied from the init_amd().

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
---

It seems that the same problem affects Cyrix and
Centaur/VIA cpus. Can some x86 guy inspect the
mtrr initialization code ?

arch/x86/kernel/cpu/mtrr/main.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index 58ac5d3..4bef914 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -1612,6 +1612,12 @@ void __init mtrr_bp_init(void)
} else {
switch (boot_cpu_data.x86_vendor) {
case X86_VENDOR_AMD:
+ if (boot_cpu_data.x86_model == 13 ||
+ boot_cpu_data.x86_model == 9 ||
+ (boot_cpu_data.x86_model == 8 &&
+ boot_cpu_data.x86_mask >= 8))
+ set_cpu_cap(&boot_cpu_data,
+ X86_FEATURE_K6_MTRR);
if (cpu_has_k6_mtrr) {
/* Pre-Athlon (K6) AMD CPU MTRRs */
mtrr_if = mtrr_ops[X86_VENDOR_AMD];
--
1.5.2.2


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