Re: PNP PS/2 probing racy?

[Andi Kleen <andi@firstfloor.org>]

On Thu, Jan 28, 2010 at 10:24:05PM -0800, Dmitry Torokhov wrote:
> On Thu, Jan 28, 2010 at 05:22:48PM +0100, Andi Kleen wrote:
> > On Thu, Jan 28, 2010 at 07:57:47AM -0800, Dmitry Torokhov wrote:
> > >> Hi,
> > >>
> > >> I noticed that on one test system of machine when booting the same
> > >> kernel I get:
> > >>
> > >> PNP: No PS/2 controller found. Probing ports directly.
> > >> serio: i8042 KBD port at 0x60,0x64 irq 1
> > >> serio: i8042 AUX port at 0x60,0x64 irq 12
> > >>
> > >> and sometimes on another boot
> > >>
> > >> PNP: PS/2 Controller [PNP0303:PS2K,PNP0f03:PS2M] at 0x60,0x64 irq 1,12
> > >>
> > >> Since I presume the BIOS does not change, is it possible the Linux
> > >> procedure for this PNP probe is racy? I haven't checked the code so far.
> > >>
> > >
> > > Are you using KVM with that box by any chance?
> > 
> > Yes, it uses a KVM, but the console was always on it.
> > 
> 
> That is wierd... Was it on the whole time (including the time when BIOS
> was doing the initialization)? Anyway i8042 expects to find all PNP

I think so. That is of course the KVM might have a special state
when the display is off, but it's hard for me to detect that.
But I didn't switch the display

> devices already enumerated by the time its initialization runs. When
> you see that message about PS2 controller not found do you see PNP0303
> and PNP0f03 if you do:
> 
> 	for i in /sys/devices/pnp0/00*; do echo -n "$i: "; cat $i/id; done

I'll check next time (machine out of reach right now)

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.