Re: [PATCH v3 5/5] ACPI / processor_idle: Add support for Low Power Idle(LPI) states

From: Sudeep Holla
Date: Tue Apr 12 2016 - 10:29:52 EST




On 12/04/16 05:06, Vikas Sajjan wrote:
Hi Sudeep,


On Wed, Dec 2, 2015 at 7:40 PM, Sudeep Holla <sudeep.holla@xxxxxxx> wrote:

[...]

diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index 29f787b2493f..bfc59de0ce6b 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -90,7 +90,7 @@ static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
pr->performance_platform_limit);
break;
case ACPI_PROCESSOR_NOTIFY_POWER:
- acpi_processor_cst_has_changed(pr);
+ acpi_processor_power_state_has_changed(pr);

The function acpi_processor_power_state_has_changed() has a check as below,

if (nocst)
return -ENODEV;

So was wondering if the platform supports only _LPI and _CST is not
supported, the 'nocst' module param passed will be 1,
and function will return -ENODEV.


You are right, it needs to be handled correctly. Thanks for spotting this.

Hence, with the introduction of LPI, should we be handling "nocst"
appropriately.
Similar is the case in function int acpi_processor_hotplug(struct
acpi_processor *pr);


Correct.

Let me know, if i am missing something here.


I don't think so. Once again thanks for the review.

--
Regards,
Sudeep