OpenBoot 3.x Command Reference Manual

pcia and pcib PCI Busses

The Sun Ultra 30 UPA/PCI system has two PCI busses, pcia & pcib. The probing of slots for those busses are controlled by the following two NVRAM configuration variables.

Table E-1 PCI Slots

Variable Name 

Default value 




Controls probe order of plug-in devices under pcia



Controls probe order of plug-in devices under pcib

pcia-probe-list corresponds to devices under /pci@1f,2000 and pcib-probe-list corresponds to devices under /pci@1f,4000.

pcia supports one plug-in client (slot 1, marked as "PCI 1, 66" ). It can support a device which is 64 bits wide and runs up to 66Mhz. Even though there is no client/slot under pcia corresponding to value 2, 2 is included in pcia-probe-list default value for historical reasons.

pcib supports three plug -in clients (slot 2,4, and 5; marked as "PCI 2", "PCI 3", and "PCI 4" respectively). pcib can support devices which are 64 bits wide and run upto 33Mhz.