PCI bridge optimization

Jon Lewis (jlewis@inorganic5.fdt.net)
Fri, 27 Sep 1996 10:22:27 -0400 (EDT)


What is the current status of PCI bridge optimization? I recently
upgraded a few servers from 2.0.1x to 2.0.21 and finally decided to
compile in PCI bridge optimization. Last night, one crashed after running
about 2.5 days. It seems to have crashed just after finishing the local
and remote backups, and was just going to start verifying them. Nothing
interesting was logged.

On a warm reboot, its SCSI disk was not detected. I hit the reset switch
again, and again it started to boot and the SDMS info displayed, but no
disk was detected. After turning the system off, waiting a few seconds,
and turning it back on, all was well.

The bootup messages dealing with optimization were:
PCI bridge optimization.
Cache L2: Not supported.
CPU-PCI posted write: on.
CPU-Memory posted write: off.Changed! Now on.
PCI-Memory posted write: on.
PCI burst: on.

The system is a 1.5 year old AIR dual P90 (only 1 CPU installed) with
AIC-7870 (turned off) built into the board and NCR 810 (using NCR53C8XX
driver) controlling a Micropolis 3243 and AHA-1540 controlling a Conner
DAT.

/proc/pci contains the following:
PCI devices found:
Bus 0, device 14, function 0:
Non-VGA device: NCR 53c810 (rev 1).
Medium devsel. IRQ 15. Master Capable. Latency=64.
I/O at 0xf800.
Non-prefetchable 32 bit memory at 0xffbeff00.
Bus 0, device 12, function 0:
SCSI storage controller: Adaptec AIC-7870 (rev 0).
Medium devsel. Fast back-to-back capable. Master Capable. No
bursts. Min Gnt=8.Max Lat=8.
I/O at 0xffffff00.
Non-prefetchable 32 bit memory at 0xfffff000.
Bus 0, device 2, function 0:
Non-VGA device: Intel 82375EB (rev 4).
Medium devsel. Master Capable. Latency=248.
Bus 0, device 0, function 0:
Host bridge: Intel 82434LX Mercury/Neptune (rev 17).
Slow devsel. Master Capable. Latency=64.

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