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authorDave Jones <davej@redhat.com>2005-05-31 19:03:45 -0700
committerDave Jones <davej@redhat.com>2005-05-31 19:03:45 -0700
commit91350ed49bf3613e243c2e216228cd4ae8f32516 (patch)
tree4c9e99fe077224e678bdd03353d37efe1f5af81e /arch/i386/kernel/cpu
parentbf6fc9fd2d848d06b8f6c4caccef1dba9ef8c4c6 (diff)
[CPUFREQ] Recalibrate cpu_khz [1/2]
We have to recalibrate cpu_khz in order to use the current FID instead the max FID since some BIOS do not put the processor at maximum frequency at POST. Also, some BIOS will change the processor frequency at our back after cpu_khz was calibrate. Finally, this will fix a long standing bug when we do something like this: # rmmod powernow-k7 # modprobe powernow-k7 Signed-off-by: Bruno Ducrot <ducrot@poupinou.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Dave Jones <davej@redhat.com>
Diffstat (limited to 'arch/i386/kernel/cpu')
-rw-r--r--arch/i386/kernel/cpu/cpufreq/powernow-k7.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/i386/kernel/cpu/cpufreq/powernow-k7.c b/arch/i386/kernel/cpu/cpufreq/powernow-k7.c
index 80f01b00bad..5c530064eb7 100644
--- a/arch/i386/kernel/cpu/cpufreq/powernow-k7.c
+++ b/arch/i386/kernel/cpu/cpufreq/powernow-k7.c
@@ -23,6 +23,7 @@
#include <linux/dmi.h>
#include <asm/msr.h>
+#include <asm/timer.h>
#include <asm/timex.h>
#include <asm/io.h>
#include <asm/system.h>
@@ -586,8 +587,12 @@ static int __init powernow_cpu_init (struct cpufreq_policy *policy)
rdmsrl (MSR_K7_FID_VID_STATUS, fidvidstatus.val);
- /* A K7 with powernow technology is set to max frequency by BIOS */
- fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.MFID];
+ /* recalibrate cpu_khz */
+ result = recalibrate_cpu_khz();
+ if (result)
+ return result;
+
+ fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.CFID];
if (!fsb) {
printk(KERN_WARNING PFX "can not determine bus frequency\n");
return -EINVAL;