Hi Sudeep,
On 5/11/2016 9:37 AM, Sudeep Holla wrote:
> +
> +static int acpi_processor_get_lpi_info(struct acpi_processor *pr)
> +{
> + int ret, i;
> + struct acpi_lpi_states_array *info;
> + struct acpi_device *d = NULL;
> + acpi_handle handle = pr->handle, pr_ahandle;
> + acpi_status status;
> +
> + if (!osc_pc_lpi_support_confirmed)
> + return -EOPNOTSUPP;
> +
> + max_leaf_depth = 0;
> + if (!acpi_has_method(handle, "_LPI"))
> + return -EINVAL;
> + flat_state_cnt = 0;
> +
> + while (ACPI_SUCCESS(status = acpi_get_parent(handle, &pr_ahandle))) {
> + if (!acpi_has_method(handle, "_LPI"))
> + continue;
> +
> + acpi_bus_get_device(handle, &d);
> + if (!strcmp(acpi_device_hid(d), ACPI_PROCESSOR_CONTAINER_HID))
> + break;
> +
> + max_leaf_depth++;
> + handle = pr_ahandle;
> + }
> +
In the above loop, we break when we find a device with HID == ACPI_PROCESSOR_CONTAINER_HID.
Shouldn't we continue to parse as long as the parent HID == ACPI_PROCESSOR_CONTAINER_HID?
This is required to make sure we parse states in levels higher than cluster level
in processor hierarchy.
Also, I think it might be safe to break out of the loop if we didn't find _LPI
package, instead of continuing. Given the presence of LPI entry: "Enabled Parent
State", I can't think of a non-ambiguous scenario where we might find LPI packages
in state N and N+2, but not in N+1, as we will not be able to figure out which
state in N enables which states in N+2. Thoughts?
Thanks,
Prashanth
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