Wednesday 08/09/2010

This month's meetings

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IRC Nick

Amit Kucheria


Amit Arora


Vishwanath Sripathy


Bobby Bhatacharia


Srinivas Kalaga


Yong Shen



  • Review action items from last meeting
  • Blueprint status



Master blueprint for PM WG


PM Tools






  • Release tasks

Action Items from this Meeting

  • Yong: test mainline u-boot on babbage 3.0
  • Yong: help Jeremy to patch his common clock api to work on babbage 3.0
  • Amit A: work with Amit K to identify and document requirements/interfaces for powerdebug (for future platforms)
  • Amit A: get powertop into a PPA, send email to list
  • Vishwa: working to refactor assembly routines for save/restore/wfi
  • Everyone: help testing linaro images

Action Items from Previous Meeting

  • ACTIVE (Immediate):
    • Yong: test against 2.6.35 mainline tree + jeremy's patches on babbage 3.0 board: done
    • Vishwa: measure latency of SRAM functions to see if different cache behavious has any effect on context save and restore: done (more actions)
    • Yong: to work with John Rigby and Ubuntu kernel team to make sure the Linaro kernel contains powertop kernel patches: pending
    • Amit A: powertop/powerdebug packaging: in progress
    • Everyone: Help with testing of Linaro images
    • Everyone: Confirm availability for LDS in Orlando and if there are any blockers
    • ACTION: Amit K to spend some time on usecase to reproduce ondemand governor problems: POSTPONED
    • Amit K (added post meeting): looking into merging linux-pm branch into Linaro
    • ACTION: ARM to share internal instrumentation flow (BAB: we might also align with Linaro on workload discussions)
      • Might take couple of months
    • ACTION: Amit K to talk to jeremy about power domain framework: DONE
      • Jeremy needs help, will revisit in a few weeks
    • ACTION: Srinivas to provide details of where he believes userspace - kernel interaction is required. (low prio)
    • ACTION: Bobby to check on multi-core boards availability (request open)
    • ACTION: ARM to discuss giving out internal Eclipse based tool (similar to powertop) (no ETA as of now)
    • ACTION: Amit Kucheria and Vishwa to get inputs from community on the issues related to CPUIDLE governor: POSTPONED until instrumentation work


  • LDS attendance
    • Bobby & Vishwa confirmed

  • Spend time testing Linaro images
  • i.MX51 mainline test on Babbage3.0 by Yong
    • mainline kernel works
    • jeremy's common clk api patches worked with some changes (to discuss with jk)
    • test u-boot as well
  • Latency variance to execute SRAM code
    • Shutdown time dominated by amount of time to clean the L2
    • depends L2 -> L3 latency

    • try putting entire code in DDR
      • refactor assembly code - separate save, restore, wfi routines called from C code
      • allows instrumentation in C code between assembly calls
      • still not completely SoC-independent since some registers (secure) might not be accessible on all SoCs

      • ARM doing work to separate secure and unsecure save and restore
  • Last call to get patches integrated into upstream/ubuntu
    • Package into PPAs while we work through upstream and ubuntu freeze exceptions

WorkingGroups/PowerManagement/Meetings/2010-09-08 (last modified 2010-09-08 09:01:12)