Re: Early ATA devices

[Tejun Heo <htejun@gmail.com>]

Alan Cox wrote:
> So I've been doing a scan of the code versus the early ATA specifications
> (English translation not the original Latin ;))
> 
> I've found a couple of problem cases we don't deal with but I'm not sure
> matter, and an inconsistency
> 
> #1	We assume identify works. Early ATA actually lists this command
> as optional
> #2	We don't allow for INIT_DEV_PARAMS failing which it may do on
> some early IDE pre ATA devices
> 
> and the inconsistency
> 
> We check ATA < 4 || non-LBA capable when deciding whether to issue
> INIT_DEV_PARAMS. ATA 4+ however mandate LBA so the second case isn't
> theoretically at least possible.
> 
> Aside from those cases the command issue (but not the detection paths)
> appear to be clean for everything from ST412 upwards providing a drive is
> being used in 16 head mode and does its own write precompensation
> selection.
> 
> So in theory we can persuade libata to drive original MFM/RLL disks with
> relatively few changes

Does anyone have a working device to test?

-- 
tejun