kern/147086: AHCI not being enabled on PC

Alexander Motin mav at
Wed May 26 18:40:09 UTC 2010

The following reply was made to PR kern/147086; it has been noted by GNATS.

From: Alexander Motin <mav at>
To: Ryan Holt <ryan at>
Cc: Garrett Cooper <yanefbsd at>, bug-followup at
Subject: Re: kern/147086: AHCI not being enabled on PC
Date: Wed, 26 May 2010 21:38:20 +0300

 Ryan Holt wrote:
 >> I've got a fresh install of FreeBSD 8.0-Stable-201004 built on a Gigabyte GA-K8U-754 Motherboard. The boot drives are plugged directly into the Motherboard's SATA ports, which I believe is powered by a ULi M1689 chipset. I also have a Supermicro AOC-SAT2-MV8 PCI-X HBA card which has a Hercules-2 Rev. C0 SATA host controller built in. I've added ahci_load="YES" in my /boot/loader.conf and I can see that ahci.ko was loaded using klstat, but I do not see any drives appearing that use the ahci module. All d rives are labeled /dev/ad* instead of /dev/ada* and hotswap doesn't work properly. Running dmesg |grep -i ahci comes back empty.
 I can't say about ULi SATA - I haven't tried any of them. Make sure that
 you have AHCI mode enabled in BIOS. ahci(4) driver should attach to any
 hardware that reporting AHCI compatibility via PCI class/subclass.
 Supermicro AOC-SAT2-MV8 - is not AHCI compatible. New driver for it
 named mvs(4). It was merged to 8-STABLE just a few weeks ago. You may
 update your system and try it.
 Alexander Motin

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