[Bug 668837] [NEW] link_power_management setting is always max_performance

[Steve Langasek]

Public bug reported:

powertop offers me the option to save power by enabling SATA ALPM link
power management.  Even if I accept its suggestion, it offers again,
because my system shows 6 SATA hosts and I'm only able to toggle the
power policy on three of them:


$ ls -l /sys/class/scsi_host/
total 0
lrwxrwxrwx 1 root root 0 2010-10-29 18:08 host0 -> ../../devices/pci0000:00/0000:00:1f.2/host0/scsi_host/host0
lrwxrwxrwx 1 root root 0 2010-10-29 18:08 host1 -> ../../devices/pci0000:00/0000:00:1f.2/host1/scsi_host/host1
lrwxrwxrwx 1 root root 0 2010-10-29 18:08 host2 -> ../../devices/pci0000:00/0000:00:1f.2/host2/scsi_host/host2
lrwxrwxrwx 1 root root 0 2010-10-29 18:08 host3 -> ../../devices/pci0000:00/0000:00:1f.2/host3/scsi_host/host3
lrwxrwxrwx 1 root root 0 2010-10-29 18:08 host4 -> ../../devices/pci0000:00/0000:00:1f.2/host4/scsi_host/host4
lrwxrwxrwx 1 root root 0 2010-10-29 18:08 host5 -> ../../devices/pci0000:00/0000:00:1f.2/host5/scsi_host/host5
$ cat /sys/class/scsi_host/host*/link_power_management_policy
min_power
max_performance
min_power
min_power
max_performance
max_performance
$

I don't know why these hosts are always set to 'max_performance'; since
they have no devices attached it's probable that they don't actually
consume any power, but it would be nice if they still respected requests
to set the power policy so that powertop doesn't offer misleading
suggestions if nothing's actually wrong.

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: linux-image-2.6.35-22-generic 2.6.35-22.35
Regression: No
Reproducible: Yes
ProcVersionSignature: Ubuntu 2.6.35-22.35-generic 2.6.35.4
Uname: Linux 2.6.35-22-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
Architecture: amd64
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: CONEXANT Analog [CONEXANT Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER        PID ACCESS COMMAND
 /dev/snd/controlC0:  vorlon     2953 F.... pulseaudio
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf2520000 irq 47'
   Mixer name	: 'Intel IbexPeak HDMI'
   Components	: 'HDA:14f15069,17aa2155,00100302 HDA:80862804,17aa21b5,00100000'
   Controls      : 14
   Simple ctrls  : 6
Card29.Amixer.info:
 Card hw:29 'ThinkPadEC'/'ThinkPad Console Audio Control at EC reg 0x30, fw 6QHT30WW-1.11'
   Mixer name	: 'ThinkPad EC 6QHT30WW-1.11'
   Components	: ''
   Controls      : 1
   Simple ctrls  : 1
Card29.Amixer.values:
 Simple mixer control 'Console',0
   Capabilities: pswitch pswitch-joined penum
   Playback channels: Mono
   Mono: Playback [on]
Date: Sat Oct 30 13:33:45 2010
HibernationDevice: RESUME=UUID=f6ab3c43-61b4-4af7-bf03-fa3b147a1de0
InstallationMedia: Ubuntu 10.04.1 LTS "Lucid Lynx" - Release amd64 (20100816.1)
Lsusb:
 Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
 Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: LENOVO 3249CTO
ProcCmdLine: BOOT_IMAGE=/vmlinuz-2.6.35-22-generic root=/dev/mapper/hostname-root ro quiet splash
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.utf8
 SHELL=/bin/bash
RelatedPackageVersions: linux-firmware 1.38
SourcePackage: linux
dmi.bios.date: 08/23/2010
dmi.bios.vendor: LENOVO
dmi.bios.version: 6QET52WW (1.22 )
dmi.board.name: 3249CTO
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr6QET52WW(1.22):bd08/23/2010:svnLENOVO:pn3249CTO:pvrThinkPadX201:rvnLENOVO:rn3249CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 3249CTO
dmi.product.version: ThinkPad X201
dmi.sys.vendor: LENOVO

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug kernel-uncat maverick needs-upstream-testing

-- 
link_power_management setting is always max_performance
https://bugs.launchpad.net/bugs/668837
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