Hi Daniel,
(just to have it public on the list)
Am 14.06.2011 10:56, schrieb Daniel Mack:
Quite frankly, I'm not fully aware about known issues with these devices that need attention. Could you summarize which problems are left to look at?
Here's a list of the issues I'm aware of:
1. Playback clicks:
There are periodic clicks in the playback at all sample rates. They are not very noticable in normal use but when you playback a plain sine the clicks are very obvious. When we discussed it last year we suspected that the device uses "implicit feedback". For the record: When we used the device with QUIRK_AUDIO_STANDARD_INTERFACE quirks we had clickless playback at 48 kHz and 96 kHz, but playback at 44.1 kHz and 88.2 kHz was totally distorted and the kernel would eventually crash after a minute or so.
2. External clock sync
The FTU devices are capable of syncing to an external clock via SPDIF. I don't know how to switch between internal and external clock. I don't even have a second audio interface to test with.
3. Mixer control steps:
The mixer controls are working fine now but are very fine grained. Being that fine grained it is hard to control the mixer in some mixer programs like alsamixer (alsamixer-qt4 and gamix work fine). A little bit of fine tuning would be nice. But I don't know which step size the hardware actually supports.
4. Reverb unit:
The FTU devices have a reverb unit which isn't supported, yet. It's straight forward based on the basic mixer support . I've almost got it wroking except for the "Reverb Program" switch. I know how to do it, so probably there will be a patch soon.
5. "Lost" URBs:
Some users reported occasional playback distortion combined with dmesg output like this: "ALSA urb.c:480: frame 5 active: -18". I don't know if this is really related to the driver. Actually I don't think so but who knows ...
Are there any other issues?
Kind regards,
Felix