kern/138235: Hotswap with SATA drives and AHCI enabled does not work

Carsten Menke bootsy52 at
Thu Aug 27 14:50:02 UTC 2009

>Number:         138235
>Category:       kern
>Synopsis:       Hotswap with SATA drives and AHCI enabled does not work
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Aug 27 14:50:01 UTC 2009
>Originator:     Carsten Menke
>Release:        7.2
Prozesse im Unternehmen
FreeBSD server.local 7.2-RELEASE-p3 FreeBSD 7.2-RELEASE-p3 #0: Tue Aug 25 18:58:21 CEST 2009
I have a Icydock MB674SPF-B hotswap backplane attached to a Gigabyte MA78GM-UD2H Motherboard with a AMD SB710 Southbridge and AHCI enabled in the BIOS.

The good news, it works better than in Linux. However, it does not work fully, because the removal of a device is recognized, but the re-insertion of the drive is not. 

cat /var/run/devd.pipe
-subdisk6  at   on ad6
-ad6  at   on ata3
!system=DEVFS subsystem=CDEV type=DESTROY cdev=ad6

If I plug the drive back in, there is NO message generated through devd.pipe and the drive is not recognized.

The current workaround for me is:

Hotswap remove the drive

atacontrol detach ata3

Put the drive back in

atacontrol attach ata3

then everything works as expected.

Further more, I'm not able to catch the detach event generated through devd and run atacontrol detach automatically, but that's another problem

1. Remove drive
2. Insert drive

atacontrol detach ataX
atacontrol attach ataX


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