OPTION_MEMORY_MAPPED is broken

Thomas Bogendoerfer (tsbogend@bigbug.franken.de)
Mon, 25 Dec 1995 12:20:52 +0100 (MET)

I'm using kernel 1.3.49 (David's pci patches and Drew's latest patch)
on a Alpha Noname board. When I change the PERM_OPTION from io-mapped
to memory-mapped, the kernel will not boot. Instead I get following
machine check:

lca: machine check (la=0xfffffc00002084d0,pc=0xfffffc00003147e4)
Reason: access to non-existent memory (long frame):
reason: 100000084 exc_addr: fffffc00003147e4 dc_stat: 23
car: 2044dc51
A write error to b-cache occurred at address 9000030 Several other uncorr
ectable errors occurred.
Attempted to access non-existent memory.
scsi : aborting command due to timeout : pid 0, scsi0, channel 0, id 0, lun 0 Te
st Unit Ready 00 00 00 00 00
scsi0 : DANGER : command running, can not abort.

I used the memory-mapped access with rel4 (kernel 1.3.45) without
troubles.

Because I get some problems with I/O access to the NCR (bad data parity),
I'm wondering if there is a way to use _only_ memory accesses ? Even
with OPTION_MEMORY_MAPPED there are some inb()s.

Thomas.