ata(4) and NCQ

["Jonathan A. Kollasch" <jakllsch%kollasch.net@localhost>]

Hi,

I'm (again) considering adding NCQ support to the ATA subsystem.

I've gained some experience with out of order transaction completion
in a virtio block driver I've worked on, however that was rather
simplistic compared to shoehorning it into existing and somewhat
dissimilar code.

I am rather bewildered by the prospects of redesigning the whole ATA
subsystem.  Basically, I am looking for ideas on a proper design of
NCQ support, so any pointers on where to start would be appreciated.

        Jonathan Kollasch