Problems with serial console

Problems with serial console

[Juergen Gross]

Hi,

I'm trying to investigate the dom0 early boot hang on my 4-core Nehalem
system. Up to now I have not been able to get any keypress via the serial
line into the hypervisor.

With xen 3.3.1 everything (serial in- and output) works with the following xen
parameters:

kernel /boot/xen.gz console=com1 com1=38400 sync_console debug=yes loglvl=all
guest_loglvl=all crashkernel=256M@16M

With xen-unstable and the following parameters only the xen messages are seen
via the serial line, input is not possible:

kernel /boot/xen.gz console=com1 com1=38400 sync_console debug=yes loglvl=all
guest_loglvl=all crashkernel=256M-:128M@16M

What could be the reason? Any idea what I could try?


Juergen

-- 
Juergen Gross                 Principal Developer Operating Systems
TSP ES&S SWE OS6                       Telephone: +49 (0) 89 3222 2967
Fujitsu Technolgy Solutions               e-mail: juergen.gross@ts.fujitsu.com
Domagkstr. 28                           Internet: ts.fujitsu.com
D-80807 Muenchen                 Company details: ts.fujitsu.com/imprint.html

Re: Problems with serial console

[Keir Fraser]

On 05/02/2010 07:04, "Juergen Gross" <juergen.gross@ts.fujitsu.com> wrote:

> With xen-unstable and the following parameters only the xen messages are seen
> via the serial line, input is not possible:
> 
> kernel /boot/xen.gz console=com1 com1=38400 sync_console debug=yes loglvl=all
> guest_loglvl=all crashkernel=256M-:128M@16M
> 
> What could be the reason? Any idea what I could try?

I'd diff ns16550.c and serial.c against last known good versions and start
reverting patches. I don't think all that much has changed that could really
stop you receiving *any* characters. I suppose the problem could potentially
be broken irq handling elsewhere in Xen...

 -- Keir

Re: Problems with serial console

[Konrad Rzeszutek Wilk]

On Fri, Feb 05, 2010 at 08:04:55AM +0100, Juergen Gross wrote:
> Hi,
> 
> I'm trying to investigate the dom0 early boot hang on my 4-core Nehalem
> system. Up to now I have not been able to get any keypress via the serial
> line into the hypervisor.

Is this via a "real" serial interface or via IPMI/BMC? If it is the
later this patch made by Gary Grebus might help you:
http://lists.xensource.com/archives/html/xen-devel/2010-01/msg00773.html

Re: Problems with serial console

[Juergen Gross]

Konrad Rzeszutek Wilk wrote:
> On Fri, Feb 05, 2010 at 08:04:55AM +0100, Juergen Gross wrote:
>> Hi,
>>
>> I'm trying to investigate the dom0 early boot hang on my 4-core Nehalem
>> system. Up to now I have not been able to get any keypress via the serial
>> line into the hypervisor.
> 
> Is this via a "real" serial interface or via IPMI/BMC? If it is the
> later this patch made by Gary Grebus might help you:
> http://lists.xensource.com/archives/html/xen-devel/2010-01/msg00773.html

Konrad, you made my day!
With the mentioned patch serial input is working again!

Keir, could you include the mentioned patch in xen-unstable?
I think it should be included in 4.0.


Juergen

-- 
Juergen Gross                 Principal Developer Operating Systems
TSP ES&S SWE OS6                       Telephone: +49 (0) 89 3222 2967
Fujitsu Technolgy Solutions               e-mail: juergen.gross@ts.fujitsu.com
Domagkstr. 28                           Internet: ts.fujitsu.com
D-80807 Muenchen                 Company details: ts.fujitsu.com/imprint.html

Re: Problems with serial console

[Keir Fraser]

On 08/02/2010 07:27, "Juergen Gross" <juergen.gross@ts.fujitsu.com> wrote:

>>> I'm trying to investigate the dom0 early boot hang on my 4-core Nehalem
>>> system. Up to now I have not been able to get any keypress via the serial
>>> line into the hypervisor.
>> 
>> Is this via a "real" serial interface or via IPMI/BMC? If it is the
>> later this patch made by Gary Grebus might help you:
>> http://lists.xensource.com/archives/html/xen-devel/2010-01/msg00773.html
> 
> Konrad, you made my day!
> With the mentioned patch serial input is working again!
> 
> Keir, could you include the mentioned patch in xen-unstable?
> I think it should be included in 4.0.

Will do.

 K.