[PATCH] x86-64: Fix HPET timer on x460

[description from AK]

The IBM Summit 3 chipset doesn't implement the HPET timer replacement
option.  Since the current Linux code relies on it use a mixed mode with
both PIT for the interrupt and HPET counters for the time keeping.  That
was already implemented, but didn't work properly because it was still
using the last interrupt offset in HPET.  This resulted in x460 not
booting.  Fix this up by using the free running HPET counter.

Shouldn't affect any other machine because they either use full HPET mode
or no HPET at all.

TBD needs a similar 32bit fix.

Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: Bob Picco <bob.picco@hp.com>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/asm-x86_64/hpet.h b/include/asm-x86_64/hpet.h
index c20c28f5c7a0..08b75c15269a 100644
--- a/include/asm-x86_64/hpet.h
+++ b/include/asm-x86_64/hpet.h
@@ -55,6 +55,8 @@ extern int is_hpet_enabled(void);
 extern int hpet_rtc_timer_init(void);
 extern int oem_force_hpet_timer(void);
 
+extern int hpet_use_timer;
+
 #ifdef CONFIG_HPET_EMULATE_RTC
 extern int hpet_mask_rtc_irq_bit(unsigned long bit_mask);
 extern int hpet_set_rtc_irq_bit(unsigned long bit_mask);