Re: 2.6.26, PAT and AMD family 6

["Yinghai Lu" <yhlu.kernel@gmail.com>]

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On Tue, May 6, 2008 at 6:48 PM, Rene Herman <rene.herman@keyaccess.nl> wrote:
> Good day.
>
>  On 2.6.25 and below, my /proc/cpuinfo looks like:
>
>  processor       : 0
>  vendor_id       : AuthenticAMD
>  cpu family      : 6
>  model           : 7
>  model name      : AMD Duron(tm) Processor
>  stepping        : 1
>  cpu MHz         : 1312.969
>  cache size      : 64 KB
>  fdiv_bug        : no
>  hlt_bug         : no
>  f00f_bug        : no
>  coma_bug        : no
>  fpu             : yes
>  fpu_exception   : yes
>  cpuid level     : 1
>  wp              : yes
>  flags           : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov
> pat pse36 mmx fxsr sse syscall mmxext 3dnowext 3dnow ts
>  bogomips        : 2628.68
>  clflush size    : 32
>
>  while on current mainline PAT and TS (Temperature Sensor) drop from the
> feature flags:
>
>  flags           : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov
> pse36 mmx fxsr sse syscall mmxext 3dnowext 3dnow
>
>  With respect to PAT, I guess it's 9307cacad0dfe3749f00303125c6f7f0523e5616,
> "x86: pat cpu feature bit setting for known cpus" but what's this about?
>
>  Did my cpuinfo lie upto this point or shouldn't the flag be cleared? The
> commit message for that change is completely and totally unhelpful.

others like to to whitebox methods, ..., please try attach patch to
see if duron support PAT.

YH

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diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index a428ffc..81483ec 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -314,6 +314,8 @@ static void __cpuinit early_get_cap(struct cpuinfo_x86 *c)
 	case X86_VENDOR_AMD:
 		if (c->x86 >= 0xf && c->x86 <= 0x11)
 			set_cpu_cap(c, X86_FEATURE_PAT);
+		if (c->x86 == 6 && c->x86_modes == 7)
+			set_cpu_cap(c, X86_FEATURE_PAT);
 		break;
 	case X86_VENDOR_INTEL:
 		if (c->x86 == 0xF || (c->x86 == 6 && c->x86_model >= 15))