mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

ACPI: processor: perflib: Use the "no limit" frequency QoS 

commit c02d5feb6e upstream.

When _PPC returns 0, it means that the CPU frequency is not limited by
the platform firmware, so make acpi_processor_get_platform_limit()
update the frequency QoS request used by it to "no limit" in that case.

This addresses a problem with limiting CPU frequency artificially on
some systems after CPU offline/online to the frequency that corresponds
to the first entry in the _PSS return package.

Reported-by: Pratyush Yadav <ptyadav@amazon.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Pratyush Yadav <ptyadav@amazon.de>
Tested-by: Pratyush Yadav <ptyadav@amazon.de>
Tested-by: Hagar Hemdan <hagarhem@amazon.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Rafael J. Wysocki 2022-12-28 22:21:49 +01:00 committed by Greg Kroah-Hartman
parent 4148f28f98
commit ad938dd2af
1 changed files with 17 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/acpi/processor_perflib.c
View File

@ -56,6 +56,8 @@ static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
{
acpi_status status = 0;
unsigned long long ppc = 0;
s32 qos_value;
int index;
int ret;
if (!pr)
@ -75,17 +77,27 @@ static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
return -ENODEV;
}
pr_debug("CPU %d: _PPC is %d - frequency %s limited\n", pr->id,
(int)ppc, ppc ? "" : "not");
index = ppc;
pr->performance_platform_limit = (int)ppc;
pr_debug("CPU %d: _PPC is %d - frequency %s limited\n", pr->id,
index, index ? "is" : "is not");
pr->performance_platform_limit = index;
if (ppc >= pr->performance->state_count ||
unlikely(!freq_qos_request_active(&pr->perflib_req)))
return 0;
ret = freq_qos_update_request(&pr->perflib_req,
pr->performance->states[ppc].core_frequency * 1000);
/*
* If _PPC returns 0, it means that all of the available states can be
* used ("no limit").
*/
if (index == 0)
qos_value = FREQ_QOS_MAX_DEFAULT_VALUE;
else
qos_value = pr->performance->states[index].core_frequency * 1000;
ret = freq_qos_update_request(&pr->perflib_req, qos_value);
if (ret < 0) {
pr_warn("Failed to update perflib freq constraint: CPU%d (%d)\n",
pr->id, ret);