O.K. I have got my RX300 running with all four logical processors.
Problem appears to be that, at the point where the ioapics are enabled, the 
local apic on the second physical processor is not properly initialized to 
take part in the negotiations needed for lowest priority delivery mode and 
that, even though only the BSP is specified as the interrupt target the 
LOPRI delivery mode is being specified.

As a quick and dirty hack I just changed the definition of 
IOAPIC_REDLO_DEL_LOPRI to 0 (i.e. the same as IOAPIC_REDLO_DEL_FIXED) in 
sys/arch/x86/include/i82093.h

At least on the RX300 ACPI_PCI_FIXUP is not needed.


Peter O'Kane                            E-mail:peter.okane@it.nuigalway.ie
Information Technology Department,      Voice: +353 91 492527
National University of Ireland, Galway. Fax: +353 91 494501