[mythtv-users] Firewire bus occasionally locks while channel changing

[Phil Linttell]

About once a week, my SA4250HD set-top box stops responding to firewire 
channel change commands, and all subsequent recordings fail.  Plugreport 
shows nothing... no nodes at all.  However, if I just unplug the 
firewire cable from the PCI card and then plug it back in, everything 
starts working again.

I don't use firewire for recording... the recording is being done over 
USB using an HD-PVR.  I use majoridiot's mythchanger to change channels 
(previously I used sa4250_ch, but was seeing the same behaviour with 
it.)  I'm not sure I'm seeing what others refer to as a "firewire bus 
hang", because attempts to reset the bus (using mythchanger -R) fail.

I'm wondering if there's a problem with my firewire PCI card or the 
kernel drivers.  I get the following messages in dmesg:
[    1.436951] ohci1394 0000:01:07.0: PCI INT A -> Link[LNKB] -> GSI 17 
(level, low) -> IRQ 17
[    1.494038] ohci1394: fw-host0: OHCI-1394 1.0 (PCI): IRQ=[17]  
MMIO=[fcfef800-fcfeffff]  Max Packet=[2]  IR/IT contexts=[4/8]
[    1.502058] ohci1394: fw-host0: Serial EEPROM has suspicious values, 
attempting to set max_packet_size to 512 bytes
[    2.772990] ieee1394: Host added: ID:BUS[0-00:1023]  
GUID[1d1600000000e332]
[    2.790225] ieee1394: Node added: ID:BUS[0-01:1023]  
GUID[001cea905acc0000]
[    8.921223] ieee1394: raw1394: /dev/raw1394 device initialized

The firewire adapter is a Pandex 3-port PCI card.  It's only used for 
changing channels to this one STB.

Has anyone seen similar behaviour?  Any thoughts how to keep my firewire 
bus from disappearing?