mrmoore@ebay.sun.com (Mike Moore) (07/13/89)
I have some questions about the operation of the VME bus on the Sun 3/1xx machines. 1. When a device on the bus gets a SYSRESET, how much time does it have to set its base address to avoid conflict other devices? Can a slave board hold its SYSRESET low (after the specified time, as in VME spec, permission 5.4) in order to complare its own initialization, without screwing up the boot somehow? 2. In the device driver, does the xxprobe() routine's return size include space for the DMA channels? Once the system is up, can the addresses be reset? 3. What special procedures are needed during the autoconfigure process to assure the proper return of the routine? What could cause this routine to bus error on return? 4. If a device on the bus has dual-ported RAM (i.e., RAM that appears in both the VME bus space and the board's CPU bus space concurrently), how easy is it to map this area into the SUN MMU's virtual address space? Is this kosher? Thanks in advance for the assistance, Mike Moore CIM Project Manager - Sun Microsystems mrmoore@sun.com 408-276-5008