Re: [Xen-devel] Xen4.2 S3 regression?

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 07.09.12 at 12:37, Ben Guthro <ben@xxxxxxxxxx> wrote:
> On Fri, Sep 7, 2012 at 4:38 AM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
> 
>> >>> On 06.09.12 at 18:42, Ben Guthro <ben@xxxxxxxxxx> wrote:
>> > Odd.
>> > The behavior seems to change, when not running with serial output.
>>
>> Odd indeed. Could you (unless you are already) try running the
>> serial console in polling mode (i.e. without IRQ), to see whether
>> the IRQs coming from it somehow keep the system alive at a
>> certain point?
>>
>>
> I tried to do this at the end of yesterday, since you had suggested it
> previously, in this thread.
> 
> I did so by adding a ",0" to my com1 line, per the documentation - However,
> I am running with a PCI serial card, and not an "on-board" one - so my
> parameter looks like:
> 
> com1=115200,8n1,pci,0
> 
> I am not totally convinced that it is actually running in polling mode, and
> started to investigate ns16550.c to verify it was. I plan on resuming this
> investigation this morning.
> If you have any pointers on what I should be looking for - I'd appreciate
> any suggestions.
> 

The only thing you need to make sure is that at the end of
ns16550_parse_port_config() uart->irq is zero. But for PCI
that should be the default right now in -unstable (but I
think I have a patch pending to alter this in certain cases).

Jan


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