From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: Xen 4 serial hangs during boot Date: Fri, 20 Jul 2012 20:59:29 +0100 Message-ID: References: <5009B505.8030900@theshore.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5009B505.8030900@theshore.net> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "Christopher S. Aker" Cc: Andrew Cooper , xen devel List-Id: xen-devel@lists.xenproject.org On 20/07/2012 20:44, "Christopher S. Aker" 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. -- Keir > -Chris