Some questions and issues with current powertop

Thomas Müller thomas at mathtm.de
Tue May 20 03:18:59 PDT 2008


Hello :)

I have a few questions / issues:
(I'm running an up-to-date version of powertop from the subversion repository
and AFAICT all relevant kernel options are enabled.)

1. I have a SATA-CD/DVD drive and a CardReader with 4 slots which is connected via USB.
    hal tries to poll every one of these five drives, so powertop's hard coded
    suggestion to run "hal-disable-polling --device /dev/scd0" is no longer correct.

2. The newest version of hal (hal-0.5.11-0.7.rc2.fc9.x86_64) no longer
    kills the hald-addon-storage process. Instead it runs as
    "hald-addon-storage: no polling on /dev/sr0 because it is explicitly disabled".
    I have now five of these processes running and they apparently wake up often
    enough to trigger powertop's suggestion to disable polling... but as it's
    already disabled, that suggestion is misleading.

3. powertop suggests to enable SATA ALPM link power management, but it doesn't work:
> # echo min_power > /sys/class/scsi_host/host0/link_power_management_policy
> # cat /sys/class/scsi_host/host0/link_power_management_policy
> max_performance

4. powertop -d reports that the CardReader is active 100.0% of the time even though
    every one of it's slots is empty.
    I told powertop to enable USB autosuspend, but that doesn't seem to make a difference.

Any ideas why SATA ALPM link power management doesn't work and why the CardReader is
always active?

Please CC me, as I'm not subscribed.


Regards,
Thomas
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