On 21/07/16 14:34, Rafael J. Wysocki wrote:
On Tuesday, July 19, 2016 06:52:54 PM Sudeep Holla wrote:
ACPI 6.0 introduced an optional object _LPI that provides an alternate
method to describe Low Power Idle states. It defines the local power
states for each node in a hierarchical processor topology. The OSPM can
use _LPI object to select a local power state for each level of processor
hierarchy in the system. They used to produce a composite power state
request that is presented to the platform by the OSPM.
Since multiple processors affect the idle state for any non-leaf hierarchy
node, coordination of idle state requests between the processors is
required. ACPI supports two different coordination schemes: Platform
coordinated and OS initiated.
This patch adds initial support for Platform coordination scheme of LPI.
Cc: "Rafael J. Wysocki" <r...@rjwysocki.net>
Signed-off-by: Sudeep Holla <sudeep.ho...@arm.com>
---
drivers/acpi/bus.c | 14 +-
drivers/acpi/processor_driver.c | 2 +-
drivers/acpi/processor_idle.c | 462 +++++++++++++++++++++++++++++++++++-----
include/acpi/processor.h | 24 ++-
include/linux/acpi.h | 4 +
5 files changed, 446 insertions(+), 60 deletions(-)
[cut]
+static int acpi_processor_get_lpi_info(struct acpi_processor *pr)
+{
+ int ret, i;
+ acpi_status status;
+ acpi_handle handle = pr->handle, pr_ahandle;
+ struct acpi_device *d = NULL;
+ struct acpi_lpi_states_array info[2], *tmp, *prev, *curr;
+
+ if (!osc_pc_lpi_support_confirmed)
+ return -EOPNOTSUPP;
+
+ if (!acpi_has_method(handle, "_LPI"))
+ return -EINVAL;
+
+ flat_state_cnt = 0;
+ prev = &info[0];
+ curr = &info[1];
+ handle = pr->handle;
+ ret = acpi_processor_evaluate_lpi(handle, prev);
+ if (ret)
+ return ret;
+ flatten_lpi_states(pr, prev, NULL);
+
+ while (ACPI_SUCCESS(status = acpi_get_parent(handle, &pr_ahandle))) {
I should have mentioned that earlier, but forgot, sorry about that.
Assignments under while () etc are generally discouraged as (a) error-prone
and (b) confusing to static analysis tools.
So I'd do
status = acpi_get_parent(handle, &pr_ahandle);
while (ACPI_SUCCESS(status)) {
Sure, will update accordingly.
+ acpi_bus_get_device(pr_ahandle, &d);
+ handle = pr_ahandle;
+
+ if (strcmp(acpi_device_hid(d), ACPI_PROCESSOR_CONTAINER_HID))
+ break;
+
+ /* can be optional ? */
+ if (!acpi_has_method(handle, "_LPI"))
+ break;
+
+ ret = acpi_processor_evaluate_lpi(handle, curr);
+ if (ret)
+ break;
+
+ /* flatten all the LPI states in this level of hierarchy */
+ flatten_lpi_states(pr, curr, prev);
+
+ tmp = prev, prev = curr, curr = tmp;
status = acpi_get_parent(handle, &pr_ahandle);
+ }
+
OK
Apart from this the patch looks OK to me, so please only update this one
and I'll queue up the series.
Thanks, will do it shortly.
Also I found a bug in my testing creating some fake tables to test this
non-recursive logic. I have missed a pointer update in the inner loop. I
will include the below one liner in the update.
-->8
diff --git i/drivers/acpi/processor_idle.c w/drivers/acpi/processor_idle.c
index fced1df535bd..c8800b55268d 100644
--- i/drivers/acpi/processor_idle.c
+++ w/drivers/acpi/processor_idle.c
@@ -1142,6 +1142,7 @@ static int flatten_lpi_states(struct
acpi_processor *pr,
combine_lpi_states(p, t, flpi)) {
stash_composite_state(curr_level, flpi);
flat_state_cnt++;
+ flpi++;
}
}
}
--
Regards,
Sudeep
