Power Mac G5 (Late 2005): Kernel panic may cause Ethernet switch to stop responding

If a Power Mac G5 (Late 2005) kernel panics, it can cause an Ethernet switch to stop responding in rare circumstances. The following three events must happen consecutively to make the Ethernet switch lock up:

1. The switch must have negotiated a flow control Ethernet session with the client over Gigabit Ethernet.
2. That session must still be active.
3. The client then kernel panics.

The easiest way to resolve this issue is to prevent the kernel panics from happening. Short of that, there are two other methods to keep the switches from locking up: Turn off flow control in the Gigabit Ethernet switch, or turn off flow control on the Mac client.

To learn how to turn off flow control on the switch, please refer to your manufacturer's documentation.

To turn off flow control on the Mac client:

1. From the Apple menu, choose System Preferences.
2. Click Network to display the pane.
3. From the Show pop-up menu, choose Built-in Ethernet.
4. Click the Ethernet tab.
5. From the Configure pop-up menu, choose Manually (Advanced).
6. From the Speed pop-up menu, choose 1000baseT.
7. From the Duplex pop-up menu, choose full-duplex.
8. Click Apply Now.