From mboxrd@z Thu Jan  1 00:00:00 1970
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: Xen 4 serial hangs during boot
Date: Mon, 23 Jul 2012 10:13:44 -0400
Message-ID: <20120723141344.GA793@phenom.dumpdata.com>
References: <5009B505.8030900@theshore.net>
 <CC2F7731.4643E%keir@xen.org>
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To: Keir Fraser <keir@xen.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>, xen devel <xen-devel@lists.xensource.com>
List-Id: xen-devel@lists.xenproject.org

On Fri, Jul 20, 2012 at 08:59:29PM +0100, Keir Fraser wrote:
> On 20/07/2012 20:44, "Christopher S. Aker" <caker@theshore.net> 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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