WOL Deskpro 3Com

[Donal Rogers_1]

Hi all,
I have a Deskpro EP PIII 600 (don't ask!), with CentOS/Red Hat 4 installed across 3 40GB HDDs. I can't get Wake On LAN to work. My NIC is a 3Com 3C905B-TX, with the correct WOL cable.

I know for a fact that all the hardware is good, because I installed Windows 2000 on to the box to check, and I was able to wake it up remotely. I shut down the Windows disk and re-connected the Linux ones. The first time I tried to wake it up, it worked. "Great!", I thought. The second, and subsequent, times I tried it, it didn't.

I have tried disabling the firewall - no change. I have tried two different Magic Packet generators on my Windows box - no change.

Does anyone have any ideas? I can't believe that it is a Windows-only feature!

Regards,

Donal.

[Matti_Kurkela]

3Com 3C905B-TX's WOL feature disables itself automatically. Unless the operating system "re-arms" it each time it is booted, WOL behaves just as you noticed: first time it works, second time it doesn't.

Windows 2000's driver will handle the re-arming automatically, unless you deliberately disable it.

Linux's driver for 3c905 cards (known as 3c59x) can re-arm the WOL, but does not do it by default. Edit /etc/modprobe.conf, add this line:

options 3c59x enable_wol=1 global_enable_wol=1

(In principle, either of those two options should be enough; however, this is the exact setting from a computer I just woke up using WOL, so this setting certainly works for me.)

Next time the driver module is loaded, it will re-arm the WOL system automatically. So, you will need to reboot once before the system is ready to wake up with the WOL feature.

A software-based firewall might limit you from sending the WOL packet, but it will not prevent the card from receiving the packet. First, the WOL packet is detected at the hardware level; second, when the system is shut down, there is no software or OS running, so any software-based firewalls are out of the picture.

[Donal Rogers_1]

Thank you for that suggestion. I will try that tonight and report back to let you know how I got on.

Regards,

Donal.

[Donal Rogers_1]

Matti,

5 points for the suggestion - it didn't work, but it increased my knowledge!

I tried inserting that line you suggested, but it made no difference.

Can you suggest anything else?

Donal.

[Matti_Kurkela]

Hmm... I looked into the 3c59x module source, and it appears that the WOL arming is connected to the ACPI subsystem in Linux. The actual arming happens just before the card (and the entire system) is powered down.

I think that means several things must be correct for the 3C905B WOL to work on Linux:

- the ACPI power management must be in use
- the 3c59x kernel module must not be unloaded as a part of the shutdown; it must be in memory when the OS invokes the ACPI powerdown
- the system must be powered down cleanly through the OS, using the ACPI powerdown system call

My computer with the working 3c905 WOL is running Debian Linux. Unfortunately I don't have a computer available which would both be free for experiments and have a 3c905 card.