kern/164694: Regression in 3726 port multiplier support in 9.0
allen at gtf.org
Thu Feb 2 18:10:09 UTC 2012
The following reply was made to PR kern/164694; it has been noted by GNATS.
From: Allen Belletti <allen at gtf.org>
To: bug-followup at freebsd.org
Subject: Re: kern/164694: Regression in 3726 port multiplier support in 9.0
Date: Thu, 02 Feb 2012 13:08:13 -0500
I've reached a dead end but come up with a few more bits of information.
It's definitely some sort of irq setup/handling problem. I
experimented with setting hint.siis.X.msi=1 for these cards.
Surprisingly, they almost seem to work. They're able to immediately
detect the pmp device and recognize the four disks on the other side of
it. However, after a few seconds of I/O, it'll get stuck and time out.
Presumably MSI just doesn't work on these cards which is why it
defaults to disabled (I've seen hints of problems like that in my
search.) I did also try forcing hint.siisch.X.sata_rev=1 but it didn't
seem to improve the situation, which makes sense if it's fundamentally
an interrupt handling problem.
It's unlikely that I can get any further on my own, but it seems likely
that some sort of IRQ handling problem was introduced between 8.2 and 9.0.
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