Bug 16463

Summary:	aic7xxx: fails to notice if a disk is unplugged
Product:	SCSI Drivers	Reporter:	Rich Ercolani (rercola)
Component:	Other	Assignee:	scsi_drivers-other
Status:	RESOLVED OBSOLETE
Severity:	normal	CC:	alan
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.32-24-generic	Subsystem:
Regression:	No	Bisected commit-id:

Description Rich Ercolani 2010-07-25 21:27:18 UTC

I have an external 7-disk array of SCA disks, connected to a backplane, with a disk module that speaks 40-pin Fast SCSI:
[   15.992335] scsi0 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 7.0
[   15.992336]         <Adaptec 2940 SCSI adapter>
[   15.992337]         aic7870: Single Channel A, SCSI Id=7, 16/253 SCBs

I was testing my RAID-6 setup on these, so I yanked one of them while they were in an MD. dmesg didn't report any change in disk status, and while any IO to the disk stalled in state D forever, Linux never noticed the disk was gone.

I tried using the convenient script I keep around for forcing rescans of SCSI and its related friends, which can be found at http://bash.cyberciti.biz/diskadmin/rescan-linux-scsi-bus/, but even after running that, the controller still didn't notice the disk was missing.