Adaptec AHA-2940U2W "Data Parity Error Dectected" messages

[Daniel Pittman <daniel@rimspace.net>]

I recently installed a SCSI tape drive and Adaptec AHA-2940U2W SCSI
controller into my server to run backups.

Since then, the driver issues these warnings on a semi-regular basis
while the drive is busy:

Aug  9 17:00:26 anu kernel: scsi0: Data Parity Error Detected during address or write data phase
Aug  9 17:00:26 anu kernel: scsi0: PCI error Interrupt at seqaddr = 0x8

[...]

Aug  9 17:03:34 anu kernel: scsi0: Data Parity Error Detected during address or write data phase

[...]

Aug  9 17:04:36 anu kernel: scsi0: PCI parity error checking has been disabled.
Aug  9 17:04:36 anu kernel: scsi0: Some device on this bus is generating bad parity.
Aug  9 17:04:36 anu kernel: scsi0: This is an error *observed by*, not *generated by*, this controller.
Aug  9 17:04:36 anu kernel: scsi0: Too many PCI parity errors observed as a target.
Aug  9 17:04:36 anu kernel: scsi0: WARNING WARNING WARNING WARNING


Now, the log message claims that the SCSI controller is not responsible
for these parity errors, so my questions are:

* should I panic about this?
* should I have seen this before the SCSI controller was installed?
* can I do anything about it, or identifying the cause?

Thanks,
      Daniel