Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit a2b7b01c authored by Len Brown's avatar Len Brown
Browse files

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: default avatarLen Brown <len.brown@intel.com>
parent 152a649b

drivers/acpi/processor_idle.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -447,7 +447,7 @@ static void acpi_processor_idle(void) 




		pr->power.bm_activity <<= diff;

		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) {

		if (bm_status) {

			pr->power.bm_activity |= 0x1;

			pr->power.bm_activity |= 0x1;

			acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);

			acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
@@ -1383,7 +1383,7 @@ static int acpi_idle_bm_check(void) 
{

{

	u32 bm_status = 0;

	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)

	if (bm_status)

		acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);

		acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);

	/*

	/*