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authorThomas Renninger <trenn@suse.de>2009-04-22 13:48:30 +0200
committerDave Jones <davej@redhat.com>2009-06-15 11:49:41 -0400
commit86e13684aa77f07c77db352f437d9e53a84dde90 (patch)
treecb0f11906c2aa6bca40b41d5b686de3957af4cf9
parentcef9615a853ebc4972084f7e70b52892557420ac (diff)
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[CPUFREQ] powernow-k8: Set transition latency to 1 if ACPI tables export 0
This doesn't fix anything, but it's expected that a transition latency of 0 could cause trouble in the future. Signed-off-by: Thomas Renninger <trenn@suse.de> Cc: Langsdorf, Mark <mark.langsdorf@amd.com> Signed-off-by: Dave Jones <davej@redhat.com>
-rw-r--r--arch/x86/kernel/cpu/cpufreq/powernow-k8.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
index cf52215d9eb1..935989693a64 100644
--- a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
+++ b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
@@ -1046,6 +1046,19 @@ static int get_transition_latency(struct powernow_k8_data *data)
if (cur_latency > max_latency)
max_latency = cur_latency;
}
+ 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.
+ */
+ if (!boot_cpu_data.x86 == 0x11)
+ printk(KERN_ERR FW_WARN PFX "Invalid zero transition "
+ "latency\n");
+ max_latency = 1;
+ }
/* value in usecs, needs to be in nanoseconds */
return 1000 * max_latency;
}