A change to dconschat(8) will follow so that it can bomb
this address over FireWire to reset a wedged system.
Though this method is just a hack and far from perfection,
it should be useful if you don't want to go machine room
just to reset or to power-cycle a machine without
remote-managed power supply. And much better than doing:
# fwcontrol -m target-eui64
# dd if=/dev/zero of=/dev/fwmem0.2 bs=1m
Now, it's safe to call the fwohci interrupt(polling) routine while ddb/gdb
is active. After this change, a dcons connnection over FireWire can survive
bus resets even in kernel debugger.
This means that it is not too late to plug a FireWire cable after a panic
to investigate the problem.
Actually there is a small window(between a jump to kernel from loader and
initialization of dcons_crom) in which no one can take care of a bus reset.
Except that window, firewire console should keep working
from loader to reboot even with a panic and a bus reset.
(as far as you enable LOADER_FIREWIRE_SUPPORT)
- Implement dcons_ischar() and dcons_load_buffer().
- If loader passed a dcons buffer address, keep using it.
(We still need a patch to cheat memory management system.)
dcons(4): very simple console and gdb port driver
dcons_crom(4): FireWire attachment
dconschat(8): User interface to dcons
Tested with: i386, i386-PAE, and sparc64.
