Ben, thanks for the information. One of the interesting bits is that in this older kernel the FW IRQ is not reroute, as shown in your original dmesg:
[ 2.618831] firewire_ohci 0000:03:04.0: PCI IRQ 0 -> rerouted to legacy IRQ 16 Would you be able to test your (faulty) kernel by booting it with 'pci=noioapicquirk' parameters? (See the "Temporarily Add a Kernel Boot Parameter for Testing" section in https://wiki.ubuntu.com/Kernel/KernelBootParameters if you're not sure how to add boot parameters). It would also be interesting to know if mainline kernel still has this issue, as Joe suggesting in comment #2. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1005920 Title: Extremely slow performance on Firewire disk To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1005920/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
