At Mon, 18 Mar 2013 19:51:09 -0700, Gabriel M. Beddingfield wrote:
On 03/18/2013 06:49 AM, Daniel Mack wrote:
Yes, I thought about that for a while as well. In fact, the data format the device supports on these altsettings is "DSD", but that doesn't have a defined value in the UAC2 spec (and strictly speaking, DSD is not even PCM).
So when a device is as unspecific as 'raw data', there's not much we can do about that except for exposing the same level of uncertainty down to the apps, right?
Yes. We can add a new format SND_PCM_FORMAT_RAW, but it's not much better than SND_PCM_FORMAT_SPECIAL after all :)
Yes. If at all, we should add a SND_PCM_FORMAT_DSD, and a quirk for that device. But given that there is no application for DSD in userspace either, we probably don't need to care.
+1
However, more and more applications are wanting to send non-linear PCM data through ALSA. So, we probably /do/ need to care.
It depends. DSD would be still likely feasible to be sent over a PCM device, as it's an audio stream after all, but most of other non-audio data wouldn't fit with the "PCM" device.
Takashi