diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/acpi/processor_idle.c | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index ee5759bef945..36dc1d26520a 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -488,7 +488,17 @@ static void acpi_processor_idle(void) case ACPI_STATE_C3: - if (pr->flags.bm_check) { + /* + * disable bus master + * bm_check implies we need ARB_DIS + * !bm_check implies we need cache flush + * bm_control implies whether we can do ARB_DIS + * + * That leaves a case where bm_check is set and bm_control is + * not set. In that case we cannot do much, we enter C3 + * without doing anything. + */ + if (pr->flags.bm_check && pr->flags.bm_control) { if (atomic_inc_return(&c3_cpu_count) == num_online_cpus()) { /* @@ -497,7 +507,7 @@ static void acpi_processor_idle(void) */ acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1); } - } else { + } else if (!pr->flags.bm_check) { /* SMP with no shared cache... Invalidate cache */ ACPI_FLUSH_CPU_CACHE(); } @@ -509,7 +519,7 @@ static void acpi_processor_idle(void) acpi_cstate_enter(cx); /* Get end time (ticks) */ t2 = inl(acpi_gbl_FADT.xpm_timer_block.address); - if (pr->flags.bm_check) { + if (pr->flags.bm_check && pr->flags.bm_control) { /* Enable bus master arbitration */ atomic_dec(&c3_cpu_count); acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0); @@ -959,9 +969,9 @@ static void acpi_processor_power_verify_c3(struct acpi_processor *pr, if (pr->flags.bm_check) { /* bus mastering control is necessary */ if (!pr->flags.bm_control) { + /* In this case we enter C3 without bus mastering */ ACPI_DEBUG_PRINT((ACPI_DB_INFO, - "C3 support requires bus mastering control\n")); - return; + "C3 support without bus mastering control\n")); } } else { /* |