Linux Plumbers Conf 2009

Excerpt

Description

The FFADO project (www.ffado.org) provides drivers which allow an increasing number of professional firewire-based audio interfaces to be used under Linux. Over the past year a number of reliability issues have been addressed and the project is preparing for a version 2.0 release (due before LPC2009). Achieving the tight timing requirement of FFADO’s streaming code remains an outstanding issue which we hope to overcome using a streaming helper module in the kernel (leaving the complex device discovery and control code in userspace). To leverage existing software it is planned to use an ALSA-compatible PCM device model to transfer audio data to and from userspace, although some questions on the detail remain. Work on coding this new module has just commenced.

This talk will commence with a discussion of the more significant problems the project has encountered: both those which have been overcome and those which are still awaiting a final solution. Advantages of the recently merged threaded IRQ kernel infrastructure for FFADO will be highlighted. The rationale for a kernel-based solution to the timing issues will be given along with a description of the new streaming kernel module itself. Finally, the remaining interface details of the new kernel module will be raised with the intention of stimulating a discussion about the best way forward.

Tags

Audio, firewire, kernel, ALSA

Speaker

• Jonathan Woithe

  Biography

  Jonathan Woithe is a Linux developer from Adelaide in Australia. He has
  been using Linux since the early 1990s both privately and as part of his
  employment, and has been sporadically contributing small patches to the Linux kernel and various open source userspace projects for about 9 years. He is currently the maintainer of the Fujitsu laptop driver in the Linux kernel and is one of the primary developers behind the FFADO project (www.ffado.org).

  Jonathan’s formal background is in atmospheric physics. During the course of his studies and in the years since he has had the opportunity to speak at professional conferences and contribute to a number of research papers. In 2008 he presented a lightning talk on the subject of FFADO at linux.conf.au and gave a FFADO introductory talk at LinuxPlumbers 2008. In 2009 he presented a FFADO tutorial and a FFADO technical talk at linux.conf.au.