Re: [RFC PATCH 1/6] ACPI: Introduce ACPI D3_COLD state support
From: Rafael J. Wysocki <hidden>
Date: 2012-02-13 20:21:28
Also in:
linux-acpi, linux-scsi, lkml
On Monday, February 13, 2012, Lin Ming wrote:
From: Zhang Rui <rui.zhang@intel.com> If a device has _PR3._ON, it means the device supports D3_HOT. If a device has _PR3._OFF, it means the device supports D3_COLD. Add the ability to validate and enter D3_COLD state in ACPI. Signed-off-by: Zhang Rui <rui.zhang@intel.com>
This is supposed to be ACPI 5.0 support, right? So can anyone please tell me what part of the ACPI 5.0 spec is the basis of this patch, because I can't see that immediately? The only places where D3Cold is _mentioned_ are Section 7.2.12 (_PRE, which appears to be new in 5.0), Section 7.2.20 (_S0W), Section 7.2.21 (_S1W), Section 7.2.22 (_S2W), Section 7.2.23 (_S3W) and Section 7.2.24 (_S4W). None of them mentions those _PR3._ON and _PR3._OFF things above. Moreover, my understanding of the spec is that D3Cold means all of the power resources returned by _PR3 are "off" (whereas some of them will be "on" in D3hot).
quoted hunk ↗ jump to hunk
--- drivers/acpi/power.c | 4 ++-- drivers/acpi/scan.c | 10 +++++++++- 2 files changed, 11 insertions(+), 3 deletions(-)diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c index 9ac2a9f..0d681fb 100644 --- a/drivers/acpi/power.c +++ b/drivers/acpi/power.c@@ -500,14 +500,14 @@ int acpi_power_transition(struct acpi_device *device, int state) { int result; - if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3)) + if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD)) return -EINVAL; if (device->power.state == state) return 0; if ((device->power.state < ACPI_STATE_D0) - || (device->power.state > ACPI_STATE_D3)) + || (device->power.state > ACPI_STATE_D3_COLD)) return -ENODEV; /* TBD: Resources must be ordered. */diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 8ab80ba..a9d4391 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c@@ -881,8 +881,16 @@ static int acpi_bus_get_power_flags(struct acpi_device *device) device->power.flags.power_resources = 1; ps->flags.valid = 1; - for (j = 0; j < ps->resources.count; j++) + for (j = 0; j < ps->resources.count; j++) { acpi_bus_add_power_resource(ps->resources.handles[j]); + /* Check for D3_COLD support. _PR3._OFF equals D3_COLD ? */ + if (i == ACPI_STATE_D3) { + if (j == 0) + device->power.states[ACPI_STATE_D3_COLD].flags.valid = 1; + status = acpi_get_handle(ps->resources.handles[j], "_OFF", &handle); + device->power.states[ACPI_STATE_D3_COLD].flags.valid &= ACPI_SUCCESS(status); + } + }
Sorry, but this doesn't make sense to me. Power resources always have the _OFF method, right?
} /* Evaluate "_PSx" to see if we can do explicit sets */
Rafael