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[CPUFREQ] powernow-k8: Set transition latency to 1 if ACPI tables export 0

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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>
This commit is contained in:
Thomas Renninger 2009-04-22 13:48:30 +02:00 committed by Dave Jones
parent cef9615a85
commit 86e13684aa
1 changed files with 13 additions and 0 deletions
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13
arch/x86/kernel/cpu/cpufreq/powernow-k8.c
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@ -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;
}