ACPI: remove locking from PM1x_STS register reads

PM1a_STS and PM1b_STS are twins that get OR'd together
on reads, and all writes are repeated to both.

The fields in PM1x_STS are single bits only,
there are no multi-bit fields.

So it is not necessary to lock PM1x_STS reads against
writes because it is impossible to read an intermediate
value of a single bit.  It will either be 0 or 1,
even if a write is in progress during the read.
Reads are asynchronous to writes no matter if a lock
is used or not.

Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 66a9d81..ae00108 100644 (file)
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -447,7 +447,7 @@ static void acpi_processor_idle(void)
 
                pr->power.bm_activity <<= diff;
 
-               acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
+               acpi_get_register_unlocked(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
                if (bm_status) {
                        pr->power.bm_activity |= 0x1;
                        acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
@@ -1383,7 +1383,7 @@ static int acpi_idle_bm_check(void)
 {
        u32 bm_status = 0;
 
-       acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
+       acpi_get_register_unlocked(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
        if (bm_status)
                acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
        /*