Woops, I forgot the attachments. Attached now :)

On Fri, Jun 19, 2009 at 11:38 AM, Marc Bowes[off-list ref] wrote:

Hi,

Tejun, the motherboard is a Gigabyte EP45-DQ6. Attached are dmidecode
and a new dmesg.txt, as I have enabled AHCI mode.

Robert,
0a:00.0 SATA controller: JMicron Technologies, Inc. JMicron
20360/20363 AHCI Controller (rev 02)
0a:00.1 IDE interface: JMicron Technologies, Inc. JMicron 20360/20363
AHCI Controller (rev 02)
Those are the two JMicron controllers I have. I assume you mean the
SATA one. The AHCI controller is:
00:1f.2 SATA controller: Intel Corporation 82801JI (ICH10 Family) SATA
AHCI Controller
I'm not sure if just that controller will be sufficient? Anyways, I
will experiment.

Thanks

On Fri, Jun 19, 2009 at 6:00 AM, Tejun Heo[off-list ref] wrote:

quoted

Robert Hancock wrote:

quoted

On 06/16/2009 09:21 AM, James Bottomley wrote:

quoted

On Tue, 2009-06-16 at 17:03 +0200, Marc Bowes wrote:

quoted

Sorry to bother, but this is really bugging me! I can't seem to find
anybody
else with the same problem. What steps should I be taking to figure this
out? I'm thinking I should be trying other kernel versions and/or
plugging
drives in different places. I don't think the motherboard is faulty,
and I
seem to be getting good speeds (~70mbs) to all four drives.

Well, those are on the AHCI built in controller. The one with the slow
response is the empty JMicron 20360/20363.  But why this should be so,
I've no idea ... it looks like the AHCI driver can't tell the phys are
empty for some reason, which could be due to many things.

I would suspect it's a hardware problem that we can't do much about..
For some reason the controller is reporting the SATA link is online at
3Gbps when there's actually nothing connected. We try to repeatedly
reset the "device" as it doesn't respond properly, until we finally give
up.

Can you disable that JMicron controller in the BIOS somehow?

It could be some storage controller hanging off there.  Some revisions
of SIMG PMPs operating in raid mode keep the link online while failing
to respond to reset if the downstream ports are empty.  Marc, which
motherboard are you using?  Can you please post the output of
dmidecode?

Thanks.

--
tejun