WRT 2.4, Ed Vance put this fix into 2.4:

 According to the data sheet, the OX16PCI952 has port 0 in BAR0 and
 port 1 in BAR1. (unlike the OX16C954, BTW) The 921600 base baud value
 is your oscillator rate divided by the default oversample rate, 16.

Since 2.6 PCI IDs have been updated to use the real device ID for
this part, we really should include this fix as well.