Re: [PATCH] take 48-bit lba a bit further

[Alan Cox]

On Sul, 2003-04-06 at 14:32, John Bradford wrote:
> Then, don't we want to be using 48-bit lba all the time on compatible devices
> instead of falling back to 28-bit when possible to save a small amount of
> instruction overhead?  (Or is that what we're doing already?  I haven't really
> had the time to follow this thread).

The overhead of the double load of the command registers is microseconds so it
is actually quite a lot, especially since IDE lacks TCQ so neither end of the
link is doing *anything* useful. SCSI has similar problems on older SCSI with 
command sending being slow, but the drive is at least doing other commands during
this.