[dm-devel] HPA unlock during partition scan of RAID components

[Phillip Susi]

On 11/4/2011 10:48 AM, Tejun Heo wrote:
> I frankly don't care about BIOSen locking up afterwards and I don't
> think they are more common than the issues from not unlocking (e.g.
> moving harddrive to another machine, hot-plugging - partition -
> reboot).  There will be a kernel param to disable unlocking behavior

Could you clarify what issues you refer to?  Moving a drive to another 
machine?

> and that would be it.  On top of that if bios is that screwed it's
> probably a good idea to not use bios raid which is a silly thing to
> begin with.  Currently the problem is that the kernel doesn't unlock
> by default and the heuristics can't be turned off, so we have unhappy
> customers on both sides.  Anyways, if md/dm people are on board, I'm
> gonna push for that but otherwise there isn't much point.

It isn't only a problem for bios raid, it also affects mdadm raid. 
Being able to defeat the heuristic would help, but I still don't see why 
the heuristic should be implemented in the kernel instead of user space?