a7y18lte-ubports/android_kernel_samsung_universal7885
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

ACPI: remove locking from PM1x_STS register reads

Browse Source 
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>
This commit is contained in:
Len Brown 2009-01-28 12:47:15 -05:00
parent 152a649b64
commit a2b7b01c07
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/acpi/processor_idle.c
View File

@ -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);
/* /*