On Wed, 09 Feb 2011 14:36:22 -0500 Phillip Susi <psusi@xxxxxxxxxx> wrote: > On 2/9/2011 10:37 AM, Alan Cox wrote: > > Unlocking the HPA is actually necessary for sanity on a lot of systems > > Right.. ones that were partitioned using an older kernel with the buggy > behavior of unlocking it by default. It would be constructive to take a more general view of the situation than trying to assign blame and complaints. > The ATA spec describes the HPA saying: > > A reserved area for data storage outside the normal operating system > file system is required for several > specialized applications. Correct. The vendors however primarily used it for completely different things. Also trusting the BIOS is generally not a good idea. > ubuntu forums and bug tracker each year of people with HPA problems and > it always seems to be a small area, as opposed to hiding everything > above 128 MB or something. Possibly because we unlock them in the distro cases. > > "Should we unlock" is almost an academic debate given we are the OS and > > control the commands sent to the drive anyway. > > Again, Linus's tree does not unlock, and should not since the bios > presumably had a reason for locking it in the first place ( it stores > something there ). I think you miss the point. If you always unlock the drive then the software behaviour can be to either honour or ignore the HPA. The HPA is a combination of two things 1. An indication from the drive that there are two sets of geometry patterns 2. A crude hack from the proprietary "we know better" world. So the best option from a kernel point of view appears to be to unlock the drive but to remember and enable user space to retrieve the parameters. In essence "what geometry do I care about" is policy for application code like dmraid, and it can be better refined there. However we can't refine it there if we don't unlock. -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
