| # Copyright (c) 2013 The Chromium OS Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| |
| import logging |
| import os |
| import traceback |
| |
| import factory_common # pylint: disable=W0611 |
| from cros.factory.goofy import service_manager |
| from cros.factory.utils.file_utils import WriteFile |
| |
| THERMAL_SERVICE = 'thermal' |
| RETRY_COUNT = 3 |
| |
| class CpufreqManager(object): |
| """Manager for CrOS-specific services that mess with cpufreq. |
| |
| If disabled, we disable CrOS-specific cpufreq management (i.e., the |
| "thermal" service) and lock down the CPU speed. |
| |
| Properties: |
| enabled: Whether cpufreq services are currently enabled |
| (or None if unknown). |
| cpufreq_path: Path to the cpufreq directory. |
| cpu_speed: CPU speed when cpufreq services are disabled. This |
| defaults (very arbitrarily) to 1.3 GHz but may be modified by |
| board-specific hooks. |
| event_log: If set, an event log object to use to log changes to enablement. |
| """ |
| enabled = None |
| cpufreq_path = '/sys/devices/system/cpu/cpu0/cpufreq' |
| cpu_speed_hz = 1300000 |
| |
| def __init__(self, event_log=None): |
| self.event_log = event_log |
| |
| def Stop(self): |
| """Stops the cpufreq manager. |
| |
| This simply returns cpufreq handling to the default state (enabled). |
| """ |
| self.SetEnabled(True) |
| |
| def SetEnabled(self, enabled): |
| """Sets whether CrOS-specific cpufreq scaling services are enabled.""" |
| if self.enabled == enabled: |
| return |
| |
| # Retry several times, since as per tbroch, writing to scaling_* |
| # may be flaky. |
| for retry_count in range(RETRY_COUNT): |
| thermal_service_status = (service_manager.Status.START if enabled |
| else service_manager.Status.STOP) |
| governor = 'interactive' if enabled else 'userspace' |
| cpu_speed_hz = None if enabled else self.cpu_speed_hz |
| |
| logging.info('cpufreq: setting thermal_service_status=%s, governor=%s, ' |
| 'cpu_speed_hz=%s, retry_count=%d', |
| thermal_service_status, governor, cpu_speed_hz, retry_count) |
| |
| if (service_manager.GetServiceStatus(THERMAL_SERVICE) != |
| thermal_service_status): |
| service_manager.SetServiceStatus(THERMAL_SERVICE, |
| thermal_service_status) |
| |
| success = False |
| exception = None |
| try: |
| WriteFile(os.path.join(self.cpufreq_path, 'scaling_governor'), |
| governor, log=True) |
| if not enabled: |
| WriteFile(os.path.join(self.cpufreq_path, 'scaling_setspeed'), |
| self.cpu_speed_hz, log=True) |
| success = True |
| except: # pylint: disable=W0702 |
| logging.exception('Unable to set CPU scaling parameters') |
| exception = traceback.format_exc() |
| |
| if self.event_log: |
| self.event_log.Log( |
| 'set_cpu_speed', |
| thermal_service_status=thermal_service_status, |
| cpu_speed_hz=cpu_speed_hz, |
| governor=governor, |
| success=success, |
| exception=exception, |
| retry_count=retry_count) |
| |
| if success: |
| break |
| |
| if success: |
| self.enabled = enabled |
| else: |
| logging.warn('Gave up on trying to set CPU scaling parameters') |
