This patch series enhances the ACPI CPPC CPUFREQ driver with
comprehensive support for autonomous performance selection, expanded
runtime control interfaces and improvements.
It adds support for below:
- Expose sysfs to read/write the Minimum/Maximum Performance Registers
using frequency (kHz), with internal conversion to performance values.
Also, update the policy min/max accordingly.
/sys/.../cpufreq/policy*/min_perf and max_perf
- Expose sysfs to read/write the Performance Limited Register.
/sys/.../cpufreq/policy*/perf_limited
- When toggling autonomous selection, synchronize the policy limits
by updating the policy min/max.
- System-wide autonomous mode configuration via 'auto_sel_mode' boot
parameter. Mode can be switched dynamically on individual CPUs.
- Generic sysfs helper functions to reduce code duplication.
The patches are grouped as below:
- Patch 1, 2 & 3: Improvements. Can be applied independently.
- Patch 4: Sysfs to update min/max_perf. Can be applied independently.
- Patch 5: Sysfs to update perf_limited. Can be applied independently.
- Patch 6: add sysfs documentation. Depends on 'Patch 4 and 5'.
- Patch 7: sync policy min/max with auto_select. Depends on 'Patch 4'.
- Patch 8: Boot Parameter Support. Depends on 'Patch 4 and 7'.
---
v3[3] -> v4:
- patch1: changed param order for show/store and moved them above use.
- patch3: write epp and auto_sel registers independently.
- patch4:
- move mutex define outside macro.
- return EOPNOTSUPP error also to the caller to handle appropriately.
- change min/max_perf sysfs to accept freq, convert to perf internally
- patch6:
- update dates and corrected names in description.
- remove dependency of min/max_perf on auto_sel.
- add info about highest_perf and lowest_perf interfaces.
- update info about min/max_perf interface to read/write freq in kHz.
v2[2] -> v3:
- drop changes to rename exisiting APIs.
- add new 'patch 1' with generic helpers for sysfs show/store.
- used guard(mutex)() in place of mutex_lock/unlock.
- update kernel-parameters text to 'enable if supported by hardware'.
- disable auto_sel for all cpus if one fails in auto_sel_mode.
- use min/max_perf values if set from bootloader.
- general code improvements, error handling and reduced redundancies.
v1[1] -> v2:
- Move CPC register set sysfs from acpi_cppc to cpufreq directory.
- No sysfs to set auto_sel and epp. They were merged from diff series.
- Remove 'cppc_cpufreq_epp' instance of the 'cppc_cpufreq' driver.
- Synchronize perf_min/max with policy min/max.
- Update policy min/max Toggling auto_select.
- add sysfs to update the perf_limited register.
Sumit Gupta (8):
cpufreq: CPPC: Add generic helpers for sysfs show/store
ACPI: CPPC: Add cppc_get_perf() API to read performance controls
ACPI: CPPC: extend APIs to support auto_sel and epp
ACPI: CPPC: add APIs and sysfs interface for min/max_perf
ACPI: CPPC: add APIs and sysfs interface for perf_limited register
cpufreq: CPPC: Add sysfs for min/max_perf and perf_limited
cpufreq: CPPC: update policy min/max when toggling auto_select
cpufreq: CPPC: add autonomous mode boot parameter support
.../ABI/testing/sysfs-devices-system-cpu | 46 ++
.../admin-guide/kernel-parameters.txt | 12 +
drivers/acpi/cppc_acpi.c | 196 +++++++-
drivers/cpufreq/cppc_cpufreq.c | 425 ++++++++++++++++--
include/acpi/cppc_acpi.h | 39 +-
5 files changed, 676 insertions(+), 42 deletions(-)
[1] https://lore.kernel.org/lkml/20250211103737.447704-1-sumitg@nvidia.com/
[2] https://lore.kernel.org/lkml/20250823200121.1320197-1-sumitg@nvidia.com/
[3] https://lore.kernel.org/lkml/20251001150104.1275188-1-sumitg@nvidia.com/
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2.34.1