From: FFADO <ffa...@ff...> - 2012-09-18 23:28:42
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#363: RME Fireface 800 random latency ---------------------------+------------------------------------------------ Reporter: juanramon | Owner: jwoithe Type: bug | Status: new Priority: major | Milestone: FFADO 3.0 Component: devices/rme | Version: FFADO SVN (trunk) Resolution: | Keywords: latency frames Device_name: | ---------------------------+------------------------------------------------ Changes (by jwoithe): * owner: jwhoite => jwoithe * milestone: => FFADO 3.0 Comment: With the current FFADO streaming architecture there may not be a lot we can do about this. The problem is that the RME streaming system works in a rather different way to most other firewire devices, and it was an interesting exercise to get it to operate within the framework of FFADO (which was designed with a more conventional setup in mind). Some parts of the FFADO streaming system are utilised in unusual ways within the RME driver and I can quite understand that this may give rise to the behaviour you have seen. When time allows (over the next week or so) I will run some tests myself to see if I can pin this down in more detail, but that may still not provide a way forward given the framework the driver has to work within. We'll see; if not possible to eliminate, there may be an opportunity to minimise the effect. Off the top of my head I strongly suspect it's due to a combination of the startup procedure we have to use and what we have to do to ensure the first start after powering the device on doesn't produce a short burst of high amplitude digital noise from the outputs. For what it's worth I expect that when I move the RME streaming driver into the kernel (ETA completely unknown at this stage, but in my mind this will probably correspond to a FFADO 3) things will work better in this regard because there will be no need to work with a higher level streaming infrastructure. Of course this doesn't help in the present, but it shows that there is a longer-term solution possible. -- Ticket URL: <http://subversion.ffado.org/ticket/363#comment:1> FFADO <http://subversion.ffado.org/index.fcgi> Free Firewire Audio Drivers |