Pyserial and Ubuntu Linux kernel 3.13.0-65-generic

Laura Creighton lac at openend.se
Sat Oct 3 05:12:28 EDT 2015


In a message of Sat, 03 Oct 2015 11:07:04 +0200, Laura Creighton writes:
>In a message of Fri, 02 Oct 2015 22:36:23 -0000, Rob Gaddi writes:
>>So, this is odd.  I'm running Ubuntu 14.04, and my system did a kernel 
>>upgrade from the repository from 3.13.0-63-generic to 3.13.0-65-generic.  
>>And pyserial (2.7, installed through pip) stopped working.
>>
>>Specifically, when I make read() calls on a Serial object, I get the error
>>
>>serial.serialutil.SerialException: device reports readiness to read but 
>>returned no data (device disconnected?)
>>
>>This comes from the PosixSerial.read() method in serialposix.py, and 
>>seems to be a result of the select.select call screwing up.
>>
>>I reboot under 3.13.0-63-generic.  My code works.  I reboot under 
>>3.13.0-65-generic.  My code doesn't.  Implication would seem to be that 
>>somehow between these kernel versions, the select() logic in the serial 
>>driver changed.  This happens regardless of whether the serial port is 
>>real, FTDI USB-UART, or Prolific USB-UART.
>>
>>Can anyone else confirm?  Also, who do I try to report this one to?
>>
>>Thanks,
>>Rob
>>
>>-- 
>>Rob Gaddi, Highland Technology -- www.highlandtechnology.com
>>Email address domain is currently out of order.  See above to fix.
>>-- 
>>https://mail.python.org/mailman/listinfo/python-list
>
>I think you have this bug
>https://bugs.launchpad.net/ubuntu/+source/linux/+bug/460857
>
>or rather, you like the behaviour that ubuntu thinks is buggy,
>which never got fixed, and don't like that it changed to be
>what ubuntu thinks is correct in .65.
>
>I'd talk to the pyserial issue tracker as the people there ought
>to be well aware of this problem, and then see if talking to
>ubuntu is the right thing to do.
>
>Laura
>-- 
>https://mail.python.org/mailman/listinfo/python-list

I think I said that poorly.

What I think happened is that ubuntu made some changes to fix this
problem, and along the way they managed to break things for you,
and maybe all pyserial users.  But I would talk to the pyserial people
about that.

Laura



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