[issue1449] AHCI panic on Intel 6321ESB AHCI

[Matthew Dillon]

:New submission from Alexander Polakov <polachok at gmail.com>:
:
:I have a panic here with AHCI enabled. See screenshot here:=20
:http://omploader.org/vMjRueA. Console gets completely unusable and fills wi=
:th=20
:garbage.
:
:DragonFly dmesg with ahci disabled:
:http://leaf.dragonflybsd.org/~polachok/dmesg.dfly
:
:OpenBSD dmesg with ahci enabled:
:http://leaf.dragonflybsd.org/~polachok/dmesg.obsd

   Under what circumstances does the panic occur?  During boot?

   The softreset sequence is supposed to be serialized, so SACT
   shouldn't have any bits set (indicating active requests), let alone
   7 bits set!

						-Matt