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authorChris McDermott <lcm@us.ibm.com>2006-02-11 17:55:50 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-11 21:41:11 -0800
commit33042a9ff4d126ba944b9dc3076665a2029e0a34 (patch)
treed5cf22cebc02316058ad860feecef20742a4ae5e
parente00d82d07fb112446586d225763d3572e64b7abf (diff)
downloadlinux-2.6.34-ux500-33042a9ff4d126ba944b9dc3076665a2029e0a34.tar.gz
[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>
-rw-r--r--arch/x86_64/kernel/apic.c2
-rw-r--r--arch/x86_64/kernel/time.c12
-rw-r--r--include/asm-x86_64/hpet.h2
3 files changed, 12 insertions, 4 deletions
diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
index 6147770b434..7a0a3e8d5d7 100644
--- a/arch/x86_64/kernel/apic.c
+++ b/arch/x86_64/kernel/apic.c
@@ -708,7 +708,7 @@ static void setup_APIC_timer(unsigned int clocks)
local_irq_save(flags);
/* wait for irq slice */
- if (vxtime.hpet_address) {
+ if (vxtime.hpet_address && hpet_use_timer) {
int trigger = hpet_readl(HPET_T0_CMP);
while (hpet_readl(HPET_COUNTER) >= trigger)
/* do nothing */ ;
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index dba7237be5c..3c58c30506a 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -59,7 +59,7 @@ static int notsc __initdata = 0;
unsigned int cpu_khz; /* TSC clocks / usec, not used here */
static unsigned long hpet_period; /* fsecs / HPET clock */
unsigned long hpet_tick; /* HPET clocks / interrupt */
-static int hpet_use_timer; /* Use counter of hpet for time keeping, otherwise PIT */
+int hpet_use_timer; /* Use counter of hpet for time keeping, otherwise PIT */
unsigned long vxtime_hz = PIT_TICK_RATE;
int report_lost_ticks; /* command line option */
unsigned long long monotonic_base;
@@ -326,7 +326,10 @@ static noinline void handle_lost_ticks(int lost, struct pt_regs *regs)
print_symbol("rip %s\n", regs->rip);
if (vxtime.mode == VXTIME_TSC && vxtime.hpet_address) {
printk(KERN_WARNING "Falling back to HPET\n");
- vxtime.last = hpet_readl(HPET_T0_CMP) - hpet_tick;
+ if (hpet_use_timer)
+ vxtime.last = hpet_readl(HPET_T0_CMP) - hpet_tick;
+ else
+ vxtime.last = hpet_readl(HPET_COUNTER);
vxtime.mode = VXTIME_HPET;
do_gettimeoffset = do_gettimeoffset_hpet;
}
@@ -988,7 +991,10 @@ void __init time_init_gtod(void)
notsc = 1;
if (vxtime.hpet_address && notsc) {
timetype = hpet_use_timer ? "HPET" : "PIT/HPET";
- vxtime.last = hpet_readl(HPET_T0_CMP) - hpet_tick;
+ if (hpet_use_timer)
+ vxtime.last = hpet_readl(HPET_T0_CMP) - hpet_tick;
+ else
+ vxtime.last = hpet_readl(HPET_COUNTER);
vxtime.mode = VXTIME_HPET;
do_gettimeoffset = do_gettimeoffset_hpet;
#ifdef CONFIG_X86_PM_TIMER
diff --git a/include/asm-x86_64/hpet.h b/include/asm-x86_64/hpet.h
index c20c28f5c7a..08b75c15269 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);