From a71e4917dc0ebbcb5a0ecb7ca3486643c1c9a6e2 Mon Sep 17 00:00:00 2001 From: Len Brown Date: Tue, 21 Apr 2009 00:50:11 -0400 Subject: [PATCH 1/2] ACPI: idle: mark_tsc_unstable() at init-time, not run-time The c2 and c3 idle handlers check tsc_halts_in_c() after every time they return from idle. Um, when?:-) Move this check to init-time to remove the unnecessary run-time overhead, and also to have the check complete before the first entry into the idle handler. ff69f2bba67bd45514923aaedbf40fe351787c59 (acpi: fix of pmtimer overflow that make Cx states time incorrect) replaced the hard-coded use of the PM-timer inside idle, with ktime_get_readl(), which possibly uses the TSC -- so it is now especially prudent to detect a broken TSC before entering idle. http://bugzilla.kernel.org/show_bug.cgi?id=13087 Signed-off-by: Len Brown --- drivers/acpi/processor_idle.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 6fe121434ffb..9d1f01ee65db 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -581,6 +581,11 @@ static int acpi_processor_power_verify(struct acpi_processor *pr) for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { struct acpi_processor_cx *cx = &pr->power.states[i]; +#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86) + /* TSC could halt in idle, so notify users */ + if (tsc_halts_in_c(cx->type)) + mark_tsc_unstable("TSC halts in idle");; +#endif switch (cx->type) { case ACPI_STATE_C1: cx->valid = 1; @@ -871,11 +876,6 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev, kt2 = ktime_get_real(); idle_time = ktime_to_us(ktime_sub(kt2, kt1)); -#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86) - /* TSC could halt in idle, so notify users */ - if (tsc_halts_in_c(cx->type)) - mark_tsc_unstable("TSC halts in idle");; -#endif sleep_ticks = us_to_pm_timer_ticks(idle_time); /* Tell the scheduler how much we idled: */ @@ -989,11 +989,6 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev, spin_unlock(&c3_lock); } -#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86) - /* TSC could halt in idle, so notify users */ - if (tsc_halts_in_c(ACPI_STATE_C3)) - mark_tsc_unstable("TSC halts in idle"); -#endif sleep_ticks = us_to_pm_timer_ticks(idle_time); /* Tell the scheduler how much we idled: */ sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS); From 92614610774072ea68131f16e024ee8fc15be9be Mon Sep 17 00:00:00 2001 From: Len Brown Date: Wed, 22 Apr 2009 19:28:15 -0400 Subject: [PATCH 2/2] ACPI: delete obsolete "bus master activity" proc field Linux-2.6.29 deleted the legacy ACPI idle handler, leaving the CPU_IDLE handler, which does not track bus master activity. So delete the unused bm_activity field -- it is confusing to print an always zero value. This patch could break programs that parse /proc/acpi/processor/*/power, since it deletes this line from that file: bus master activity: 00000000 http://bugzilla.kernel.org/show_bug.cgi?id=13145 is not fixed by this patch, but provoked this patch. Signed-off-by: Len Brown --- drivers/acpi/processor_idle.c | 4 +--- include/acpi/processor.h | 1 - 2 files changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 9d1f01ee65db..eed3b458ebac 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -662,11 +662,9 @@ static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset) seq_printf(seq, "active state: C%zd\n" "max_cstate: C%d\n" - "bus master activity: %08x\n" "maximum allowed latency: %d usec\n", pr->power.state ? pr->power.state - pr->power.states : 0, - max_cstate, (unsigned)pr->power.bm_activity, - pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY)); + max_cstate, pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY)); seq_puts(seq, "states:\n"); diff --git a/include/acpi/processor.h b/include/acpi/processor.h index b09c4fde9725..4927c063347c 100644 --- a/include/acpi/processor.h +++ b/include/acpi/processor.h @@ -84,7 +84,6 @@ struct acpi_processor_power { struct acpi_processor_cx *state; unsigned long bm_check_timestamp; u32 default_state; - u32 bm_activity; int count; struct acpi_processor_cx states[ACPI_PROCESSOR_MAX_POWER]; int timer_broadcast_on_state;