Revert "[PATCH] x86_64: Only do the clustered systems have unsynchronized TSC assumption on IBM systems"

This reverts commit 13a229abc25640813f1480c0478dfc6bdbc1c19e.

Quoth Andi:
  "After some consideration and feedback from various people it turns
   out this wasn't that good an idea.  It has some problems and needs
   more work.  Since it was only an optimization anyways it's best to
   just back it out again for now."

Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 8 deletions

diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
index d70605eda333..e5b14c57eaa0 100644
--- a/arch/x86_64/kernel/apic.c
+++ b/arch/x86_64/kernel/apic.c
@@ -962,14 +962,12 @@ void smp_apic_timer_interrupt(struct pt_regs *regs)
         irq_exit();
 }
 
-int __initdata unsync_tsc_on_multicluster;
-
 /*
  * oem_force_hpet_timer -- force HPET mode for some boxes.
  *
  * Thus far, the major user of this is IBM's Summit2 series:
  *
- * Some clustered boxes may have unsynced TSC problems if they are
+ * Clustered boxes may have unsynced TSC problems if they are
  * multi-chassis. Use available data to take a good guess.
  * If in doubt, go HPET.
  */
@@ -979,11 +977,6 @@ __cpuinit int oem_force_hpet_timer(void)
         unsigned id;
         DECLARE_BITMAP(clustermap, NUM_APIC_CLUSTERS);
 
-        /* Only do this check on IBM machines - big Unisys systems
-           use multiple clusters too, but have synchronized TSC */
-        if (!unsync_tsc_on_multicluster)
-                return 0;
-
         bitmap_zero(clustermap, NUM_APIC_CLUSTERS);
 
         for (i = 0; i < NR_CPUS; i++) {