Re: bus_dmamap_sync() for USB

[David Young <dyoung%pobox.com@localhost>]

On Tue, Jun 24, 2008 at 03:24:46PM +0200, Manuel Bouyer wrote:
> On Tue, Jun 24, 2008 at 08:49:41AM -0400, Michael Lorenz wrote:
> > This sounds like a good explanation of what I'm seeing.
> > I'll try your latest patch later today - you said you fixed another  
> > race condition(s).
> > This leaves the question why the ohci/ehci board just works in much  
> > faster machines ( namely an 800MHz G4 and a dual 450MHz US-II ) - I'd  
> > expect them to be more sensitive to race conditions like that. On the  
> > other hand, they might just be fast enough for the CPU to (almost)  
> > always win the race.
> 
> This is one explaination. Interrupt latency may also play a role; I had
> much more troubles under Xen than with native amd64. 

What do you think the role of interrupt latency is?

Dave

-- 
David Young             OJC Technologies
dyoung%ojctech.com@localhost      Urbana, IL * (217) 278-3933 ext 24