wake-on-lan after power loss ( doesn't work).

  • Thread starter Thread starter H Brett Bolen
  • Start date Start date
H

H Brett Bolen

My motherboard ( supermicro x5dal-g) has wake on lan which normally
works fine.

However if power is removed ( ie I shutdown normally, unplug
it, then plug it back in ), the machine does not wake up.

Has anybody had a problem with this ( or got it to work)?

I suspect that it is not a problem with other adaptors.

Thanks
b²
 
My first guess would be to check the BIOS for an option that sounds like
"After power loss..." Alot of boards have an option in the BIOS that keeps
them from powering on automatically after power loss, i.e. power surge,
power plug removed then plugged back in.

Thats my best guess
-Chris
 
My motherboard ( supermicro x5dal-g) has wake on lan which normally
works fine.

However if power is removed ( ie I shutdown normally, unplug
it, then plug it back in ), the machine does not wake up.

Has anybody had a problem with this ( or got it to work)?

I suspect that it is not a problem with other adaptors.
Click to expand...

Nobody with a properly designed motherboard will get the above scenario to
work - because:

- WOL "wakes" only from the "Standby" state,
- and the "Standby" state depends on memory data being kept alive.
- When you lose the mains power to the system, the memory data is lost
- and the system power controller recognizes it is no longer in the "Standby"
state
- hence there will be no WOL function available...

/daytripper
 
daytripper said:
Nobody with a properly designed motherboard will get the above scenario to
work - because:

- WOL "wakes" only from the "Standby" state,
- and the "Standby" state depends on memory data being kept alive.
- When you lose the mains power to the system, the memory data is lost
- and the system power controller recognizes it is no longer in the "Standby"
state
- hence there will be no WOL function available...
Click to expand...

WOL and "boot on power restore" are two different things. What you say is
true for WOL, but with power removed, the real time clock in the BIOS is still
active. All that is needed, is a circuit to turn on the power supply when
mains power is restored. Some BIOSs do have this circuit. The BIOS can
then respond to a WOL request.

Virg Wall
 
WOL and "boot on power restore" are two different things. What you say is
true for WOL, but with power removed, the real time clock in the BIOS is still
active. All that is needed, is a circuit to turn on the power supply when
mains power is restored. Some BIOSs do have this circuit. The BIOS can
then respond to a WOL request.

Virg Wall
Click to expand...

No, that won't give you WOL. The bios switch you're referring to cannot return
the system to the *Standby* state, so there's no way WOL will function.

In addition to the requirement I provided, I left out at least one other
critical need for WOL to function. Think about how WOL works and you should
quickly arrive at the correct conclusion...

/daytripper (hint: the bios has nothing to do with it...)
 
daytripper said:
No, that won't give you WOL. The bios switch you're referring to cannot return
the system to the *Standby* state, so there's no way WOL will function.
Click to expand...

It doesn't need WOL--the system is fully up. You can set the power management
to go to "Standby" if you wish to wait for a WOL. Of course the NIC, or
whatever
is connected to the LAN must be active.
 
It doesn't need WOL--the system is fully up.
Click to expand...

And that's *not* WOL, which was the whole point of the thread, eh?

That's simply "Power Up after AC loss", already noted...

/daytripper
 
daytripper said:
And that's *not* WOL, which was the whole point of the thread, eh?
Click to expand...

You left out this part of my answer:

"You can set the power management
to go to "Standby" if you wish to wait for a WOL."
That's simply "Power Up after AC loss", already noted...

/daytripper
Click to expand...

Virg Wall
 
Hi
I'm using WakeOnLAN and I've some questions.
I would like to know :

- When you enable WakeOnLAN in the Windows driver. Where is saved this
parameter ? In ACPI Tables ? In Windows Registry ? In a Network Card Memory
?

- At shutdown, the NIC puts into a WakeOnLAN mode ? or just in a certain
electrical state which allows WakeOnLAN ?

- If I understand what you say first, after a powerfailure, when electricty
comes again, the PC isn't in Standby state. But is the WakeOnLAN enabled at
this moment ?

Excuse me for my english...
Thanks
 
In addition to the requirement I provided, I left out at least one other
critical need for WOL to function. Think about how WOL works and you should
quickly arrive at the correct conclusion...
Click to expand...
/daytripper (hint: the bios has nothing to do with it...)
Click to expand...

ok I'll bite.

what? ( another pc, power, ethernet)
 
You left out this part of my answer:

"You can set the power management
to go to "Standby" if you wish to wait for a WOL."

Virg Wall
Click to expand...

Sorry - the generic use of "power management" so close to a bios discussion
left me at the bios level, not the os.

Ok, so to review, if the OP sets the bios to enable "Power Up after AC loss",
has it automatically boot the OS, has the nic driver configured to enable WOL,
and has the OS power management configured to always go to Standby after N
minutes, then yeah, that'd work, because you're NOT trying to do the
impossible of getting from a full power down state to "WOL-ready".

You'd sure want N to be fairly large though...which might reduce the
practicality of such a work-around...

/daytripper
 
Hi
I'm using WakeOnLAN and I've some questions.
I would like to know :

- When you enable WakeOnLAN in the Windows driver. Where is saved this
parameter ? In ACPI Tables ? In Windows Registry ? In a Network Card Memory
?
Click to expand...

The important thing is the driver then configures the nic adapter and
typically a supporting logic element (usually the SIO as most designs utilize
generic SIO GPIO pins to support WOL) that will recognize the "wake me now"
signal from the NIC and in turn signal the system power control logic to tell
the main power supply to fully turn on.
- At shutdown, the NIC puts into a WakeOnLAN mode ? or just in a certain
electrical state which allows WakeOnLAN ?
Click to expand...

Careful, if you're using "shutdown" to indicate "standby". These are
significant, contrary terms. There is no return to "awake" from "shutdown",
only from "standby".

If you meant "standby", the important bits are noted above.
- If I understand what you say first, after a powerfailure, when electricty
comes again, the PC isn't in Standby state. But is the WakeOnLAN enabled at
this moment ?
Click to expand...

If the PC wasn't steadily maintained in the Standby state, WOL is not
possible. You cannot transition from the "shutdown" state to the "standby"
state. You can only WOL from "standby".

The same NIC and SIO settings that I listed earlier depend on maintaining the
"standby" aka "housekeeping" power to these elements to retain the settings.
When the system is put into the "standby" state, "standby" power is always
available as long as mains (AC) power is connected to the supply.

But if the AC disappears, the "standby" power disappears, and these dynamic
settings are lost, so WOL is not possible.
Excuse me for my english...
Thanks
Click to expand...

You're English is just fine. Whatever your native language I can assure you I
would be pitifully bad at it compared to your mastery of English ;-)

cheers

/daytripper
 
ok I'll bite.

what? ( another pc, power, ethernet)
Click to expand...

Ah - you slipped me a back-channel mail message copy of this, to which I
replied earlier. It contained the same comments I just provided on-group.

That'll teach me...

/daytripper
 
daytripper said:
Sorry - the generic use of "power management" so close to a bios discussion
left me at the bios level, not the os.
Click to expand...

There are some BIOS power management schemes. I think an OS scheme would
be better for the reasons you mention.
Ok, so to review, if the OP sets the bios to enable "Power Up after AC loss",
has it automatically boot the OS, has the nic driver configured to enable WOL,
and has the OS power management configured to always go to Standby after N
minutes, then yeah, that'd work, because you're NOT trying to do the
impossible of getting from a full power down state to "WOL-ready".

You'd sure want N to be fairly large though...which might reduce the
practicality of such a work-around...
Click to expand...

You'd need to see when the power management was loaded. If it were after
all the other drivers were set up, N could be very small. You'd have to
be sure the NIC driver and the program to accept the WOL "magic packet"
were up and running.

Even with a BIOS without "boot on power return", a handful of Radio Shack
parts will "push the button" on a return of power. All sorts of schemes
could be implemented, based on the fact that power return will provide
+5V SB from the PS, and that the BIOS boot routine is in ROM or CMOS.

Virg Wall
 
There are some BIOS power management schemes. I think an OS scheme would
be better for the reasons you mention.
Click to expand...

Perhaps with embedded nics, bios could be aware enough, but not for much
longer. What "bios" is left after the Next Big Thing is foisted upon the world
will be even less capable post code and then a quick jump to the boot block.
Leave everything else up to Redmund....
You'd need to see when the power management was loaded. If it were after
all the other drivers were set up, N could be very small. You'd have to
be sure the NIC driver and the program to accept the WOL "magic packet"
were up and running.
Click to expand...

I was thinking if N was small the poor bastard who has to actually use that
machine on prime shift would have to hover over the keyboard to keep the
damned thing awake.
Even with a BIOS without "boot on power return", a handful of Radio Shack
parts will "push the button" on a return of power. All sorts of schemes
could be implemented, based on the fact that power return will provide
+5V SB from the PS, and that the BIOS boot routine is in ROM or CMOS.
Click to expand...

Context is everything, and unless the OP expresses the desire and the ability
to cobble his/her hardware such notions are going to remain unsaid ;-)
Even so, the utility of having a system in some weird "warm but dumb" state
where a full OS load is required upon fully awakening to do anything useful
kinda escapes me...

For servers, by the way, we solve this with much more sophistication (read:
more hardware and firmware) as we in addition to such mundanities as WOL, we
have to allow a remote controlled full power-down, full power-up, reset, and
so on, and be able to remotely see what you would see on a local monitor
during post.

This capability is sold as an option specifically for lights-out sites. The
option cost is more than an entry level pc ;-)

/daytripper (there is money to be made selling convenience)
 
Thanks daytripper
I can now begin my report.
I have to make an etude of WakeOnLAN for my studies.
 
But if the AC disappears, the "standby" power disappears, and these
dynamic
settings are lost, so WOL is not possible.
Click to expand...

When electricty comes again, and you put the machine in standby mode again
(without loading OS, just from BIOS loading), "The same NIC and SIO
settings" are so lost by Power Failure, nevertheless why we can use
WakeOnLAN ?
This shows that these parameters are saved somewhere, no ?

It's the last question ;)
 
When electricty comes again, and you put the machine in standby mode again
(without loading OS, just from BIOS loading), "The same NIC and SIO
settings" are so lost by Power Failure, nevertheless why we can use
WakeOnLAN ?
This shows that these parameters are saved somewhere, no ?

It's the last question ;)
Click to expand...

Possibly it's a regiser set in the NIC, that is loaded by BIOS or OS
driver initialization, and once loaded, is preserved by 5VSB, but due
to complete power failure 5VSB is of course gone too, so NIC reverts
to defaults again, the process repeats.
 
Possibly it's a regiser set in the NIC, that is loaded by BIOS or OS
driver initialization, and once loaded, is preserved by 5VSB, but due
to complete power failure 5VSB is of course gone too, so NIC reverts
to defaults again, the process repeats.
Click to expand...

You are on the right track (I'm getting through! ;-)

But as I mentioned there's more than just the NIC, there is the on-board WOL
support that has to be set and only remains set while the SB voltages are
present. This support has traditionally been implemented using SIO ("Super IO"
chip) GPIO pins within a special section of the SIO that is kept "alive" with
the same SB power.

Lose the SB power = lose these settings = no WOL is possible...

/daytripper
 
When electricty comes again, and you put the machine in standby mode again
(without loading OS, just from BIOS loading), "The same NIC and SIO
settings" are so lost by Power Failure, nevertheless why we can use
WakeOnLAN ?
This shows that these parameters are saved somewhere, no ?

It's the last question ;)
Click to expand...

You cannot "put the machine in standby mode again without loading the OS".
Period.

After a mains power failure, you *can* reapply "standby power" to the system,
but it isn't in WOL mode any longer. Yes, because the "parameters are saved
somewhere" in the nic and motherboard WOL logic and are only preserved while
"standby power" is constantly maintained, as I explained...

/daytripper (hope I get a good grade ;-)
 
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