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Re: [Xen-devel] Xen 4 serial hangs during boot

On Fri, Jul 20, 2012 at 08:59:29PM +0100, Keir Fraser wrote:
> On 20/07/2012 20:44, "Christopher S. Aker" <caker@xxxxxxxxxxxx> wrote:
> > On 7/20/12 3:31 PM, Keir Fraser wrote:
> >> Somehow dom0 disabled the serial-line interrupt during boot. Possibly it
> >> appeared as a PnP device in some BIOS table and dom0 decided to disable it
> >> because it doesn't think it is being used. Xen would usually stop this
> >> happening via programming of the IO-APIC/XT-PIC but perhaps there is some
> >> other method of disabling it on this mainboard, which Xen doesn't catch.
> > 
> > Hmm -- except dom0 hasn't even booted yet at the time the serial stops
> > working.  Xen is 30-60 seconds away from booting dom0 given the RAM
> > scrub still has to happen.
> Then it is Xen doing something to kill the serial interrupt. ;-) I haven't
> seen anything like this reported before. Not sure what to suggest really...
> Gather debug output from interrupt-related debug keys (via the xl debug-keys
> interface) I suppose. I think that would be 'i' and 'z' keys. That plus Xen
> and dom0 boot logs... something might become apparent.

What about using the serial line without the interrupt?
Meaning com1=115200,8n1,0x3f8,0

That ought to make the code go into polling and ignore the interrupt line right?

>  -- Keir
> > -Chris
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