Garbled serial console output

Garbled serial console output

[Harmandeep Kaur]

Hi,

I tried to setup xen serial console with this guide,
http://wiki.xen.org/wiki/Xen_Serial_Console

I am using RS232 -USB cable for this purpose.
I am on Ubuntu 15.10 (4.2.0-19-generic).

xl info http://paste2.org/F2UgY5yz

My output is garbled.
http://paste2.org/tZveaAGU

I will appreciate any help.

Regards,
Harman

Re: Garbled serial console output

[Dario Faggioli]

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On Thu, 2015-12-17 at 11:58 +0530, Harmandeep Kaur wrote:
> Hi,
> 
Hello Harmandeep,

> I tried to setup xen serial console with this guide,
> http://wiki.xen.org/wiki/Xen_Serial_Console
> 
> I am using RS232 -USB cable for this purpose.
> I am on Ubuntu 15.10 (4.2.0-19-generic).
> 
> xl info http://paste2.org/F2UgY5yz
> 
> My output is garbled.
> http://paste2.org/tZveaAGU
> 
Ok. You also want to say what program, and with what
configuration/parameters, you are using to view the serial line output.

From what you said on IRC, I think that is this:

 sudo screen /dev/ttyUSB8 115200

is that correct?

I don't have many ideas about what could cause the issue, and how to
fix it. Every time I've seen something similar to that it was due to:
 - mismatch between the baud rate specified in screen command line and 
   the one configured for Xen's console
 - more than one screen session "attached" to the serial line

So, I'd first of all double check these.

You can also try something else than screen (I'm sure there are dozens
of terminal emulators on Ubuntu :-)), and see what happens.

Regards,
Dario
-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


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Re: Garbled serial console output

[Roger Pau Monné]

El 17/12/15 a les 10.06, Dario Faggioli ha escrit:
> On Thu, 2015-12-17 at 11:58 +0530, Harmandeep Kaur wrote:
>> Hi,
>>
> Hello Harmandeep,
> 
>> I tried to setup xen serial console with this guide,
>> http://wiki.xen.org/wiki/Xen_Serial_Console
>>
>> I am using RS232 -USB cable for this purpose.
>> I am on Ubuntu 15.10 (4.2.0-19-generic).
>>
>> xl info http://paste2.org/F2UgY5yz
>>
>> My output is garbled.
>> http://paste2.org/tZveaAGU
>>
> Ok. You also want to say what program, and with what
> configuration/parameters, you are using to view the serial line output.
> 
> From what you said on IRC, I think that is this:
> 
>  sudo screen /dev/ttyUSB8 115200
> 
> is that correct?
> 
> I don't have many ideas about what could cause the issue, and how to
> fix it. Every time I've seen something similar to that it was due to:
>  - mismatch between the baud rate specified in screen command line and 
>    the one configured for Xen's console
>  - more than one screen session "attached" to the serial line
> 
> So, I'd first of all double check these.
> 
> You can also try something else than screen (I'm sure there are dozens
> of terminal emulators on Ubuntu :-)), and see what happens.

FWIW, I've used screen in the past to connect to serial consoles and I
think cu is better (it doesn't have an internal scrollback buffer, and
doesn't trap Ctrl+A).

cu -l /dev/ttyUSB8 -s 115200

Roger.

Re: Garbled serial console output

[Andrew Cooper]

On 17/12/2015 06:28, Harmandeep Kaur wrote:
> Hi,
>
> I tried to setup xen serial console with this guide,
> http://wiki.xen.org/wiki/Xen_Serial_Console
>
> I am using RS232 -USB cable for this purpose.
> I am on Ubuntu 15.10 (4.2.0-19-generic).
>
> xl info http://paste2.org/F2UgY5yz
>
> My output is garbled.
> http://paste2.org/tZveaAGU

That looks very much like a misconfigured baud rate.  Given that you
were using 11520, give 9600 a go.

~Andrew

Re: Garbled serial console output

[Doug Goldstein]

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On 12/17/15 12:28 AM, Harmandeep Kaur wrote:
> Hi,
> 
> I tried to setup xen serial console with this guide,
> http://wiki.xen.org/wiki/Xen_Serial_Console
> 
> I am using RS232 -USB cable for this purpose.
> I am on Ubuntu 15.10 (4.2.0-19-generic).
> 
> xl info http://paste2.org/F2UgY5yz
> 
> My output is garbled.
> http://paste2.org/tZveaAGU
> 
> I will appreciate any help.
> 
> Regards,
> Harman

I believe on Ubuntu I've had to stop modemmanager on every machine I've
done anything with the serial port. When it comes up in dom0 it'll
diddle with all the serial ports and cause problems.

-- 
Doug Goldstein


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