Re: 2.5 IDE Whitepaper?

From: Alan Cox (
Date: Wed Aug 21 2002 - 18:51:52 EST

On Thu, 2002-08-22 at 00:32, Jeff Garzik wrote:
> > I am looking for documentation regarding the 2.5 IDE rewrite. For example:
> > What are the goals for 2.5. What is the implementation plan? What were the
> > problems in 2.4, and how will they be fixed in 2.5, etc?
> <chuckle> I wish :)
> I imagine it will happen like most things happen, Linus describes his
> ideas and goals and wishes in a few lkml posts, and eventually something
> like it happens :)

I can try, my working list approximates this (ignoring the 2.5
porting/block I/O stuff which is a chapter in itself)

Phase #1 (mostly complete)
        Merge Andre's current code [DONE]
        Remove all the bogus code from the PCI drivers [90% DONE]
        Move all the drivers seperate from the core code [DONE]
        Migrate the PCI drivers to a registration API and allow insmod
        Fix bugs arising from the first bits of phase 1

Phase #2
        Deal with insmod of a device currently running as legacy
        Fix up the locking ready to allow rmmod of a pci driver
        Allow rmmod and hotplug at the controller level

Phase #3
        Complete splitting setup-pci functions into smaller bits of code
        and replace deep magic and callbacks with functions called from
        each driver. Get all the if device==foo out of the PCI code paths

Phase #4
        Do something about the ide_register/unregister end of the world
        and legacy chipset stuff. The PPC folks may tackle this in
        Get us to the point we can foo = ide_attach(); ide_remove(foo)
        for arbitary interfaces
And then (when the setup is turned the right way out and not before)
begin looking at turning the actual block I/O engine the right way out.
(That is driver calls helpers not midlayer and magic)

That should allow us to keep solid stable IDE along the way.

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