My Ubuntu kernel is 3.19.0-31 so I think you're a bit out of date.

There is a bug in the latest Ubuntu 14.04 kernel ( 3.13-65 IIRC ) that is causing serial devices to time out reading.

Nigel A. Gunn, 1865 El Camino Drive, Xenia, OH 45385-1115, USA. tel +1 937 825 5032 Amateur Radio G8IFF W8IFF (was KC8NHF 9H3GN), e-mail nigel@ngunn.net www http://www.ngunn.net Member of ARRL, QRPARCI #11644, SOC #548, Flying Pigs QRP Club International #385, Dayton ARA #2128, AMSAT-NA LM-1691, GCARES, EAA382.