device atpic to be deprecated?

Anders Gavare gavare at
Fri Nov 9 11:26:28 PST 2007

Hi currenters!

On Wednesday 29 March 2006, John Baldwin wrote:
> On Wednesday 29 March 2006 12:08, Scott Long wrote:
> > John Baldwin wrote:
> > On Wednesday 29 March 2006 11:26, Scott Long wrote:
> ..
> >> >>>>On Wed, Mar 29, 2006 at 02:05:27AM -0600, Conrad J. Sabatier
> >> >>>>wrote:
> > >>>>>Is the plan still in effect to abolish this device?
> > >>>>
> > >>>>To my mind it wouldn't make much sense, given the sheer amount 
> > >>>>of hardware out there which doesn't have an IOAPIC, then again 
> > >>>>I'm probably out of touch with the state of interrupt handling
> > >>>>in -CURRENT.
> > >>>
> > >>>All amd64 machines (which is where atpic would be removed) have
> > >>>an APIC.
> > >>
> > >>That's kind of like saying that ISA will be removed because there
> > >>is PCI
> > >>=-) Having an APIC doesn't necessarily guarantee that it works.
> > >>There have been enough reports of problems on the mailing lists
> > >>over time that I think it's a bit premature to declare the ATPIC
> > >>dead. Also, is the ATPIC code in amd64 causing problems, holding 
> > >>back progress, or creating a maintenance burden?
> > >
> > > I think that once the lapic timer stuff was added almost all of
> > > the APIC issues I was aware of went away on amd64 that were fixed
> > > by using device atpic instead. Most of the earlier problems were
> > > due to chipsets not setting up pin 0 as extint, etc. but all that
> > > is no longer relevant when we switched to using the lapic timer
> > > and stopped using irq0 and irq8 with APIC. This is the first I've
> > > heard since the lapic timer stuff that APIC didn't work on an
> > > amd64 box, and device atpic has been off by default in HEAD for
> > > quite a while now. If we were able to require APIC on amd64, then
> > > we might be able to try out some optimizations and other things I
> > > haven't bothered with since they wouldn't be feasible on i386.
> >
> > Fine, remove it.
> I have to make sure it really works for everyone first though before
> removing it would really be viable. :-/

The GENERIC 7.0-BETA2 kernel does not boot on my 1.8 GHz amd64 laptop
(and HP Pavilion ze2000). Not in safe mode, not without ACPI, not
without apic0/sio0/sio1 (which is the usual trick on this machine).

After some detective work, however, I noticed that with "device atpic"
added, 7.0-BETA2 works fine on this machine. (I took a chance and
updated my sources from 6-STABLE to 7-STABLE, added the device, and now
I am running 7.0-BETA2. If I hadn't already had FreeBSD installed, it
would not have been possible to get it to boot, though, so this feels
kind of critical.)

My question is: Is it possible to add "device atpic" again in time for
the 7.0 release?  What is the possible negative impact of adding it?


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