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ac6 >> ac6-training >> Operating Systems >> Linux >> Power Management in Linux Drivers Download Catalog Download as PDF Write us Printable version

D7 Power Management in Linux Drivers

Writing drivers with power management support

Writing drivers with power management support
  • Configure the Linux kernel for optimal power management.
  • Understand how Linux manages the power
    • To write drivers integrated in this scheme
    • To optimize low power modes
  • Install and use power-management utilities
Labs are conducted on target boards, that can be:
    Atmel ARM9-based boards, with Lauterbach JTAG probes.
We use the last linux kernel, as supported by the board.
Course environment
  • A PC workstation and a target board per two trainees group with Lauterbach JTAG probe.
  • Printed and PDF course material.
  • Documentation and exercises solutions.
  • Good practice of C programming on Linux
  • Basic knowledge of Linux kernel and driver programming (see our D3 - Linux Drivers course)

First Day
Reminders on kernel programming
  • Reminders on kernel module development
  • Kernel objects
Exercise:  Writing a kernel module creating and using kernel objects and sets
  • The sysfs file system
Exercise:  Interacting with a kernel module through a kernel object and the sysfs file sytem
Power-management : APM and ACPI
  • The APM standard.
  • The ACPI standard.
Exercise:  Writing a user program to shut down the system.
Power-management, suspend and hibernate
  • Freezing tasks
  • Suspend in RAM
  • Suspend on Disk
  • Hibernate
  • Debugging power management
Exercise:  Writing a kernel module reacting to suspend in RAM and system wakeup
Second Day
Power management in drivers
  • Device states vs System state
  • Putting devices in low-power modes
  • Power-management operations in drivers
  • Controling system state changes from drivers
Exercise:  Adapting a device driver to put the device in suspended state when unused
Cpu frequency governors
  • The cpufreq user interface.
  • The various governors available.
Idle Cpu governors
  • The Idle task.
  • The Idle device concept.
  • CpuIdle governors.