diff options
Diffstat (limited to 'drivers/acpi/processor_idle.c')
| -rw-r--r-- | drivers/acpi/processor_idle.c | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index ed56c6d20b08..2ae95df2e74f 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -642,6 +642,19 @@ static int acpi_idle_bm_check(void) return bm_status; } +static void wait_for_freeze(void) +{ +#ifdef CONFIG_X86 + /* No delay is needed if we are in guest */ + if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) + return; +#endif + /* Dummy wait op - must do something useless after P_LVL2 read + because chipsets cannot guarantee that STPCLK# signal + gets asserted in time to freeze execution properly. */ + inl(acpi_gbl_FADT.xpm_timer_block.address); +} + /** * acpi_idle_do_entry - enter idle state using the appropriate method * @cx: cstate data @@ -658,10 +671,7 @@ static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx) } else { /* IO port based C-state */ inb(cx->address); - /* Dummy wait op - must do something useless after P_LVL2 read - because chipsets cannot guarantee that STPCLK# signal - gets asserted in time to freeze execution properly. */ - inl(acpi_gbl_FADT.xpm_timer_block.address); + wait_for_freeze(); } } @@ -682,8 +692,7 @@ static int acpi_idle_play_dead(struct cpuidle_device *dev, int index) safe_halt(); else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) { inb(cx->address); - /* See comment in acpi_idle_do_entry() */ - inl(acpi_gbl_FADT.xpm_timer_block.address); + wait_for_freeze(); } else return -ENODEV; } |