From: Borislav Petkov <borislav.petkov@xxxxxxx>
The Pstate transition latency check was added for broken F10h BIOSen which
wrongly contain a value of 0 for transition and bus master latency.
Fam11h and later, however, (will) have similar transition latency so
extend that behavior for them too.
Signed-off-by: Borislav Petkov <borislav.petkov@xxxxxxx>
Cc: Dave Jones <davej@xxxxxxxxxx>
Cc: Mark Langsdorf <Mark.Langsdorf@xxxxxxx>
Cc: Thomas Renninger <trenn@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/cpufreq/powernow-k8.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff -puN arch/x86/kernel/cpu/cpufreq/powernow-k8.c~powernow-k8-limit-pstate-transition-latency-check arch/x86/kernel/cpu/cpufreq/powernow-k8.c
--- a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c~powernow-k8-limit-pstate-transition-latency-check
+++ a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
@@ -1025,13 +1025,12 @@ static int get_transition_latency(struct
}
if (max_latency == 0) {
/*
- * Fam 11h always returns 0 as transition latency.
- * This is intended and means "very fast". While cpufreq core
- * and governors currently can handle that gracefully, better
- * set it to 1 to avoid problems in the future.
- * For all others it's a BIOS bug.
+ * Fam 11h and later may return 0 as transition latency. This
+ * is intended and means "very fast". While cpufreq core and
+ * governors currently can handle that gracefully, better set it
+ * to 1 to avoid problems in the future.
*/
- if (boot_cpu_data.x86 != 0x11)
+ if (boot_cpu_data.x86 < 0x11)
printk(KERN_ERR FW_WARN PFX "Invalid zero transition "
"latency\n");
max_latency = 1;
_
--
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