On Mon, 2009-03-02 at 18:55 +0100, Bartlomiej Zolnierkiewicz wrote:
> > Could we make just the IDE driver itself enable interrupts? Sure. But that 
> 
> Actually it has been doing it for years (some host drivers don't do this by
> default and still need "hdparm -u" or equivalent but I was planning to change
> it for 2.6.30).

What does it use to do that? A local_irq_enable() in hardirq context
will make lockdep yell bloody murder :-).

Then there is local_irq_enable_in_hardirq(), which plain simply lies
when lockdep is enabled -- IOW it would generate horrid irq latencies.

Not having to deal with IRQ recursion in lockdep helps.