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ACPI: Only use IPI on known broken machines (AMD, Dothan/BaniasPentium M) 

Use IPI for blacklisted CPUs, add parameter IPI vs LAPIC

Currently, Linux disables lapic timer for all machines with C2 and higher
C-state support.

According to Intel only specific Intel models (Banias/Dothan) are broken
in respect of not waking up from C2 with lapic.

However, I am not sure about the naming of the parameter and how it
could/should get integrated into the dyntick part
(CONFIG_GENERIC_CLOCKEVENTS). There, a more fine grained check (TSC
still running?, ..) is needed? Does this make sense (always use
CLOCK_EVT_NOTIFY_BROADCAST_ON, but use OFF if forced by use_ipi=0:
clockevents_notify(use_ipi ? CLOCK_EVT_NOTIFY_BROADCAST_ON :
CLOCK_EVT_NOTIFY_BROADCAST_OFF, &pr->id);

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
hifive-unleashed-5.1
Thomas Renninger 2007-02-27 12:13:00 -05:00 committed by Len Brown
parent db98e0b434
commit 25496caec1
1 changed files with 29 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
drivers/acpi/processor_idle.c
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@ -89,6 +89,12 @@ module_param(nocst, uint, 0000);
static unsigned int bm_history __read_mostly =
(HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
module_param(bm_history, uint, 0644);
static unsigned use_ipi = 2;
module_param(use_ipi, uint, 0644);
MODULE_PARM_DESC(use_ipi, "IPI (vs. LAPIC) irqs for not waking up from C2/C3"
" machines. 0=apic, 1=ipi, 2=auto\n");
/* --------------------------------------------------------------------------
Power Management
-------------------------------------------------------------------------- */
@ -260,9 +266,8 @@ static void acpi_cstate_enter(struct acpi_processor_cx *cstate)
/*
* Some BIOS implementations switch to C3 in the published C2 state.
* This seems to be a common problem on AMD boxen, but other vendors
* are affected too. We pick the most conservative approach: we assume
* that the local APIC stops in both C2 and C3.
* This seems to be a common problem on AMD boxen and Intel Dothan/Banias
* Pentium M machines.
*/
static void acpi_timer_check_state(int state, struct acpi_processor *pr,
struct acpi_processor_cx *cx)
@ -276,8 +281,17 @@ static void acpi_timer_check_state(int state, struct acpi_processor *pr,
if (pwr->timer_broadcast_on_state < state)
return;
if (cx->type >= ACPI_STATE_C2)
pr->power.timer_broadcast_on_state = state;
if (cx->type >= ACPI_STATE_C2) {
if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
pr->power.timer_broadcast_on_state = state;
else if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
boot_cpu_data.x86 == 6) &&
(boot_cpu_data.x86_model == 13 ||
boot_cpu_data.x86_model == 9))
{
pr->power.timer_broadcast_on_state = state;
}
}
}
static void acpi_propagate_timer_broadcast(struct acpi_processor *pr)
@ -292,10 +306,16 @@ static void acpi_propagate_timer_broadcast(struct acpi_processor *pr)
#else
cpumask_t mask = cpumask_of_cpu(pr->id);
if (pr->power.timer_broadcast_on_state < INT_MAX)
if (use_ipi == 0)
on_each_cpu(switch_APIC_timer_to_ipi, &mask, 1, 1);
else
else if (use_ipi == 1)
on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1);
else {
if (pr->power.timer_broadcast_on_state < INT_MAX)
on_each_cpu(switch_APIC_timer_to_ipi, &mask, 1, 1);
else
on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1);
}
#endif
}
@ -1013,13 +1033,13 @@ static int acpi_processor_power_verify(struct acpi_processor *pr)
case ACPI_STATE_C2:
acpi_processor_power_verify_c2(cx);
if (cx->valid)
if (cx->valid && use_ipi != 0 && use_ipi != 1)
acpi_timer_check_state(i, pr, cx);
break;
case ACPI_STATE_C3:
acpi_processor_power_verify_c3(pr, cx);
if (cx->valid)
if (cx->valid && use_ipi != 0 && use_ipi != 1)
acpi_timer_check_state(i, pr, cx);
break;
}