diff options
| author | Helge Deller <deller@gmx.de> | 2007-01-03 19:25:37 +0100 |
|---|---|---|
| committer | Kyle McMartin <kyle@athena.road.mcmartin.ca> | 2007-02-17 01:02:47 -0500 |
| commit | 324c7e6545539d2f7736be930d4833deb32b1b95 (patch) | |
| tree | 44673470df765ac7832c247ce49e58ed5885a293 /arch/parisc/kernel/time.c | |
| parent | 12df29b64c782133afea8cacc6acdad68a6b7d17 (diff) | |
[PARISC] disable cr16 clocksource when multiple CPUs are online
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Diffstat (limited to 'arch/parisc/kernel/time.c')
| -rw-r--r-- | arch/parisc/kernel/time.c | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/arch/parisc/kernel/time.c b/arch/parisc/kernel/time.c index e47e27cea42e..c33b6e0f7c47 100644 --- a/arch/parisc/kernel/time.c +++ b/arch/parisc/kernel/time.c @@ -99,7 +99,7 @@ irqreturn_t timer_interrupt(int irq, void *dev_id) * cycles after the IT fires. But it's arbitrary how much time passes * before we call it "late". I've picked one second. */ - if (ticks_elapsed > HZ) { + if (unlikely(ticks_elapsed > HZ)) { /* Scenario 3: very long delay? bad in any case */ printk (KERN_CRIT "timer_interrupt(CPU %d): delayed!" " cycles %lX rem %lX " @@ -180,6 +180,8 @@ static cycle_t read_cr16(void) return get_cycles(); } +static int cr16_update_callback(void); + static struct clocksource clocksource_cr16 = { .name = "cr16", .rating = 300, @@ -187,9 +189,25 @@ static struct clocksource clocksource_cr16 = { .mask = CLOCKSOURCE_MASK(BITS_PER_LONG), .mult = 0, /* to be set */ .shift = 22, + .update_callback = cr16_update_callback, .is_continuous = 1, }; +static int cr16_update_callback(void) +{ + int change = 0; + + /* since the cr16 cycle counters are not syncronized across CPUs, + we'll check if we should switch to a safe clocksource: */ + if (clocksource_cr16.rating != 0 && num_online_cpus() > 1) { + clocksource_cr16.rating = 0; + clocksource_reselect(); + change = 1; + } + + return change; +} + /* * XXX: We can do better than this. @@ -225,10 +243,6 @@ void __init time_init(void) current_cr16_khz = PAGE0->mem_10msec/10; /* kHz */ clocksource_cr16.mult = clocksource_khz2mult(current_cr16_khz, clocksource_cr16.shift); - /* lower the rating if we already know its unstable: */ - if (num_online_cpus()>1) - clocksource_cr16.rating = 200; - clocksource_register(&clocksource_cr16); if (pdc_tod_read(&tod_data) == 0) { |