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ACPI / PM: Use Low Power S0 Idle on more systems
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Some systems don't support the ACPI_LPS0_ENTRY and ACPI_LPS0_EXIT
functions in their Low Power S0 Idle _DSM, but still expect EC
events to be processed in the suspend-to-idle state for power button
wakeup (among other things) to work.  Surface Pro3 turns out to be
one of them.

Fortunately, it still provides Low Power S0 Idle _DSM with the screen
on/off functions supported, so modify the ACPI suspend-to-idle to use
the Low Power S0 Idle code path for all systems supporting the
ACPI_LPS0_ENTRY and ACPI_LPS0_EXIT or the ACPI_LPS0_SCREEN_OFF and
ACPI_LPS0_SCREEN_ON functions in their Low Power S0 Idle _DSM.

Potentially, that will cause more systems to use suspend-to-idle by
default, so some future corrections may be necessary if it leads
to issues, but let it remain more straightforward for now.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=198389#add_comment
Reported-by: Valentin Manea <valy@mrs.ro>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Valentin Manea <valy@mrs.ro>
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Rafael J. Wysocki committed Jan 11, 2018
1 parent 5704403 commit 29a5a6d
Showing 1 changed file with 4 additions and 2 deletions.
6 changes: 4 additions & 2 deletions drivers/acpi/sleep.c
Original file line number Diff line number Diff line change
Expand Up @@ -707,7 +707,8 @@ static const struct acpi_device_id lps0_device_ids[] = {
#define ACPI_LPS0_ENTRY 5
#define ACPI_LPS0_EXIT 6

#define ACPI_S2IDLE_FUNC_MASK ((1 << ACPI_LPS0_ENTRY) | (1 << ACPI_LPS0_EXIT))
#define ACPI_LPS0_SCREEN_MASK ((1 << ACPI_LPS0_SCREEN_OFF) | (1 << ACPI_LPS0_SCREEN_ON))
#define ACPI_LPS0_PLATFORM_MASK ((1 << ACPI_LPS0_ENTRY) | (1 << ACPI_LPS0_EXIT))

static acpi_handle lps0_device_handle;
static guid_t lps0_dsm_guid;
Expand Down Expand Up @@ -910,7 +911,8 @@ static int lps0_device_attach(struct acpi_device *adev,
if (out_obj && out_obj->type == ACPI_TYPE_BUFFER) {
char bitmask = *(char *)out_obj->buffer.pointer;

if ((bitmask & ACPI_S2IDLE_FUNC_MASK) == ACPI_S2IDLE_FUNC_MASK) {
if ((bitmask & ACPI_LPS0_PLATFORM_MASK) == ACPI_LPS0_PLATFORM_MASK ||
(bitmask & ACPI_LPS0_SCREEN_MASK) == ACPI_LPS0_SCREEN_MASK) {
lps0_dsm_func_mask = bitmask;
lps0_device_handle = adev->handle;
/*
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