Fan control for new PowerMac G5 2.7GHz machines?

[Brian D. Carlstrom]

I'm trying to get linuxppc64 fan control working on a 2.7GHz G5 machine.
I started with YDL 4.0.1's 2.6.10 kernel and already have applied the
fixup_device_tree code from:

    [PATCH] ppc64: Fix booting on latest G5 models
    http://ozlabs.org/pipermail/linuxppc64-dev/2005-May/004140.html

Its nice to be up and running but the fans are running at full speed,
similar to what I remember with YDL 4.0 and the therm_pm72 patch. 

/var/log/dmesg shows the following:
    PowerMac G5 Thermal control driver 1.1
    adb: starting probe task...
    adb: finished probe task...
    Detected fan controls:
      0: PWM fan, id 1, location: BACKSIDE,SYS CTRLR FAN
      1: RPM fan, id 2, location: DRIVE BAY
      2: PWM fan, id 2, location: SLOT,PCI FAN
      3: RPM fan, id 3, location: CPU A INTAKE
      4: RPM fan, id 4, location: CPU A EXHAUST
      5: RPM fan, id 5, location: CPU B INTAKE
      6: RPM fan, id 6, location: CPU B EXHAUST
      7: RPM fan, id 1, location: CPU A PUMP
      8: RPM fan, id 0, location: CPU B PUMP

I noticed that YDL seems to have applied the main part of this patch to
their 2.6.10 tree, as you can see from the "SYS CTRLR FAN" string,
although they left the version as "1.1":

    Patch: Thermal control for Xserve
    http://patchwork.ozlabs.org/linuxppc64/patch?id=697

Beyond the fixup_device_tree patch, I haven't seen much talk about the
status of linuxppc64 on the 2.7 GHz G5. There was this once post on
yellowdog-devel:

    g5 2.7 works with 4.0.91 beta.
    http://lists.terrasoftsolutions.com/pipermail/yellowdog-devel/2005-June/000433.html

but it's kind of sparse on the details.

Can anyone shed some light on the fan support for these new machines?
Am I just doing something simple wrong or missing something obvious?

Thanks,
-bri