Subject: Should Alpha PCI code manage latency timers?
To: None <firstname.lastname@example.org>
From: Thor Lancelot Simon <email@example.com>
Date: 01/24/2005 08:10:07
The upshot of a rather strange recent thread in netbsd-help (titled
"got drivers?") was that, at least on some PCI alphas, neither SRM
nor our MD PCI code set devices' latency timers at all. A user had
a machine with two tulips, a pciide, and a QL1040 -- only the 1040
worked reliably, because the isp driver explicitly whacks the latency
timer value to 0x40 if it finds it at 0x00.
The user adjusted the pciide driver to set the latency timer to 0x40
and all of a sudden he could use the disk and talk on the network at
the same time without losing packets.
If SRM isn't going to set the latency timer it seems to me we ought to;
and not in every device driver, either!
Thor Lancelot Simon firstname.lastname@example.org
"The inconsistency is startling, though admittedly, if consistency is to be
abandoned or transcended, there is no problem." - Noam Chomsky