Matthew Garrett wrote:

On Tue, Jul 12, 2005 at 11:49:35PM +0900, Tejun Heo wrote:

quoted

This has come up several times now.  One thing I'm curious about is 
why we are disabling HPA on boot without consent from the user.  AFAIK, 
HPA is mostly used to implement hidden recovery/suspend storage areas 
and disabling automatically on boot increases the likeliness of 
destroying them.  What do we gain by disabling HPA on boot?  Are there 
some dumb machines which unnecessarily sets HPA and reduces the capacity 
of drives excessively?  Even in such cases, wouldn't it be better to do 
idedisk_check_hpa() only when kernel parameter explicitly says so?

I'm not sure why we're doing it, but reverting this behaviour is likely 
to make some systems unbootable (install with kernel which disables HPA, 
format entire drive, put filesystem on it).

  Yeah... it will immediately make disks unusable.  sad, sad.

-- 
tejun