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SubjectRe: [PATCH v4 1/5] ACPI / processor_idle: introduce ARCH_SUPPORTS_ACPI_PROCESSOR_CSTATE
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On 20/04/16 10:56, Vikas Sajjan wrote:
> Hi Sudeep,
>
> On Tue, Apr 19, 2016 at 6:00 PM, Sudeep Holla <sudeep.holla@arm.com> wrote:
>> ACPI 6.0 adds a new method to specify the CPU idle states(C-states)
>> called Low Power Idle(LPI) states. Since new architectures like ARM64
>> use only LPIs, introduce ARCH_SUPPORTS_ACPI_PROCESSOR_CSTATE to
>> encapsulate all the code supporting the old style C-states(_CST)
>>
>> This patch will help to extend the processor_idle module to support
>> LPI.
>>

[...]

>> @@ -1018,29 +1062,11 @@ int acpi_processor_power_init(struct acpi_processor *pr)
>> acpi_status status;
>> int retval;
>> struct cpuidle_device *dev;
>> - static int first_run;
>>
>> if (disabled_by_idle_boot_param())
>> return 0;
>>
>> - if (!first_run) {
>> - dmi_check_system(processor_power_dmi_table);
>> - max_cstate = acpi_processor_cstate_check(max_cstate);
>> - if (max_cstate < ACPI_C_STATES_MAX)
>> - printk(KERN_NOTICE
>> - "ACPI: processor limited to max C-state %d\n",
>> - max_cstate);
>> - first_run++;
>> - }
>> -
>> - if (acpi_gbl_FADT.cst_control && !nocst) {
>> - status =
>> - acpi_os_write_port(acpi_gbl_FADT.smi_command, acpi_gbl_FADT.cst_control, 8);
>> - if (ACPI_FAILURE(status)) {
>> - ACPI_EXCEPTION((AE_INFO, status,
>> - "Notifying BIOS of _CST ability failed"));
>> - }
>> - }
>> + acpi_processor_cstate_first_run_checks();
>>
>> acpi_processor_get_power_info(pr);
>> pr->flags.power_setup_done = 1;
>
> Not related to your change,
> The acpi_processor_get_power_info() function can return failure, so i
> thought it makes sense to check for the return value
> and then set the flag pr->flags.power_setup_done appropriately.
>

Makes sense, will do that.

--
Regards,
Sudeep

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