Hi folks,
I am currently having problems with my new Dual Celeron testsystem,
when trying to use UDMA66.
Hardware:
ABIT BP6
2x Celeron 466 (NOT overclocked)
128 Mbyte RAM
Matrox G400 16 MByte
3Com 905B
2x Maxtor 92041U4 20 GByte
Aopen CDROM 48x
One of the disks is master on the first "standard" disk channel, and
uses
UDMA33, the other is master on the first "fast" channel controlled by
the
on-board HPT-366, and is probed as UDMA66.
When I use the UDMA33 disk, no problem occurs at all, I can even run
"make buildworld" without any problems. When accessing the disk on the
UDMA66 channel however, the system regularly hangs, followed by a
message
like:
Feb 12 12:39:54 myhost /kernel: ad4: ad_timeout: lost disk contact -
resetting
Feb 12 12:39:54 myhost /kernel: ata2: resetting devices .. done
After a few of these messages the system hangs completely, and needs to
be
rebooted.
The problem already occurred during my first attempts to use UDMA66 last
week, but now persists using today's 4.0-CURRENT.
My kernel is derived from GENERIC, with SMP added, and devices removed
that
are not present. I do not yet use softupdates.
The problem can easily be reproduced by creating a large file as
follows:
dd if=/dev/zero of=junk bs=1024k count=512
This command runs without any problem. Reading this file with:
dd if=junk of=/dev/null bs=1024k
causes the problem to occur within a few seconds. Decreasing the
blocksize
makes the system survive somewhat longer, but the problem still occurs.
Only with a blocksize lower than 4k the system does not hang.
Very strange is the fact that reading the raw device file with:
dd if=/dev/ad4s1c of=/dev/null bs=1024k
completes without problems, even with two commands running concurrently.
I already tried to swap the disks, but the problem still occurs on the
one
that is using UDMA66. Even when switching to PIO using 'sysctl', the
system
still hangs, it just takes somewhat longer before it happens.
Does anybody have an idea what happens ?
Kind regards,
Hans
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