Linux Plumbers Conf 2013

One Line Summary

Abstract

As Matthew Garrett said in an LKML post:

“ACPI and DT overlap in that they both provide a mechanism for enumerating non-enumerable devices, and both also provide a mechanism for attaching additional configuration data to devices (which may or may not be otherwise enumerable). There’s a sufficient overlap in functionality that at least one platform that’s traditionally been Device Tree (ARM) is also adding support for ACPI – there’s even ACPI-based ARM hardware on the market already.

Right now that’s a problem for us. The same hardware may end up shipped with either ACPI or DT-based firmware, and at the moment we’d need to either write two drivers or one driver with two glue layers. This is somewhat suboptimal."

Moreover, some systems are shipped with ACPI firmware whose ACPI tables do not contain all information necessary to enumerate and handle all devices, but at least in some cases there are known DT bindings for the hardware in question that could be used for this purpose.

We are going to discuss those problems and try to reach an agreement on the way to resolve them.

Tags

ACPI, Device Trees, Flattened Device Trees, DT, FDT, device enumeration

Speaker

• 

  Rafael Wysocki

  Intel OTC
  Biography

  I am the maintainer of the Linux kernel’s core power management code (PM core), cpuidle, cpufreq, and the ACPI subsystem. I work at Intel Open Source Technology Center as a Software Engineer with focus on the Linux kernel. I have been actively contributing to the Linux kernel since January 2005, working on the suspend and hibernate subsystem, on power management in general (including runtime PM, PM QoS etc.), and on the ACPI and PCI subsystems.

  Sessions

  • * ACPI-based Hotplug of PCI and Other Devices
    • Title: ACPI-based Hotplug of PCI and Other Devices
    • Microconference: ACPI/PM, PCI subsystems I
    • Time: 10:15am
    • One Line Summary:

      Discussion on the status of support for ACPI-based hotplug of devices in the Linux kernel

    • slides
    • Speakers: Rafael Wysocki
  • * PCIe Native Hotplug Integration with ACPI-Based Hotplug
    • Title: PCIe Native Hotplug Integration with ACPI-Based Hotplug
    • Microconference: ACPI/PM, PCI subsystems I
    • Time: 9:50am
    • One Line Summary:

      Discussion on how to integrate the native PCIe hotplug (pciehp) with ACPI-based PCI hotplug (acpiphp).

    • slides
    • Speakers: Rafael Wysocki
  • * PM Interfaces Between User Space and the Kernel
    • Title: PM Interfaces Between User Space and the Kernel
    • Microconference: ACPI/PM, PCI subsystems I
    • Time: 11:05am
    • One Line Summary:

      Discussion on interfaces to use for communicating the needs of user space related to power management to the kernel.

    • slides
    • Speakers: Rafael Wysocki
  • * ACPI vs DT
    • Title: ACPI vs DT
    • Microconference: ACPI/PM, PCI subsystems II
    • One Line Summary:

      ACPI vs Device Tree – Moving Forward: Discussion on device enumeration methods

    • Speakers: Rafael Wysocki