Re: pmud on iBook questions
> I've been experimenting with pmud (from sid) on my iBook FireWire.
> According to the documentation the real sleep mode does not work
> on such machines. It works fine, though. I used 'snooze -f' to be
> sure and bypass pmud and its script. Just perfect.
What do you mean by 'sleep works just perfect'? I have a hard time
believing that ... what kernel version are you running? What is the exact
model of iBook you're using?
> If pmud initiates the sleep it first turns the hds off via the
> hdparm 'workaround'. The 'fbset 0' command does nothing useful.
> Then pmud needs the disks so it takes 20 seconds to get it back
> up via an IDE reset. Now it goes to sleep properly :)
fbset 0 is a typo/thinko on my part.
Swap the order of the two hdparm calls and it might not even need the IDE
reset. I suspect the 'cat' run after forced IDE shutdown is the cause of
the IDE reset.
> Is the workaround obsolete, then?
If sleep indeed works on your part, it is obsolete.
> What does sleep mode do exactly?
Power down pretty much all peripherals (IDE, display, SCSI, serial
interfaces IIRC, _not_ ethernet) and put the CPU into low power mode.
It's not off, it still snoops on the bus where the hardware permits (G3
and up), but it will wait for a keypress to initiate the wakeup sequence.
> Can I specify inactivity timeouts for it somewhere?
Define 'inactivity'. A Linux system is never inactive.
> Any possibility for wake-on-lan (from sleep)?
I doubt it. I think the CPU will only respond to interrupts from the PMU
during sleep. Look at the kernel source to see exactly what happens.
Getting a network interrupt to wake the CPU would require kernel changes
anyway :-)
> Is there a way to turn off just the display?
fblevel off or fblevel 0.
> When the iBook is in my LAN I'd prefer to close it and ssh to it
> if I need something. Closing the lid will send it to sleep however.
This is done on purpose, and I strongly advise against bypassing this
feature. Heat dissipation by convection _through_ the keyboard is an
integral part of PowerMac laptops. Running the iBook with the lid closed
puts you at hazard of damaging the LCD and/or other parts of the machine.
But then, all we ever hear from Apple is hearsay so who knows? Try at your
own risk please.
> Sleep seems to turn off the network card... should I put ifup/ifdown
> in the script or does pmud do that itself?
Sleep doesn't turn off the network card (except for maybe PCMCIA; what's
the ethernet hardware in iBooks?). At least it shouldn't. But then,
I'm surprised sleep should work on any iBook or Pismo at all.
Maybe the iBook doesn't permit the processor to snoop on the bus in order
to detect DMA transfers from the still running ethernet card. The
processor would fail to invalidate its cache for the packets received
durng sleep, at the very least. Or it's shutting down the PCMCIA socket
as part of the sleep notifier chain (again, check the source). If so,
All of this is a kernel issue, and nothing that can be changed by pmud.
Ben Herrenschmidt is probably the best person to talk to about kernel pmu
issues.
Michael
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