On Tue, 2011-11-15 at 09:11 +0100, Takashi Iwai wrote:
For compressed path (i had posted RFC roughly two months back [1]),
we
are creating new devices /dev/snd/comprCxDxp which would be
registered
as SNDRV_DEV_COMPRESS. For the registration part we need to assign
the
minors, right? Hence the above question
Or did I miss something very obvious here...
Yes, take a look at PCM devices, for example. They have sub-streams. So, you can open a single device file multiple times to assign multiple sub-streams. If any specific substream with a given index is needed, it can be specified via ioctl before open. Otherwise, the next empty substream is assigned.
The similar implementation is found in rawmidi, too.
Okay Thanks a bunch, I wanted to avoid these kind of mistakes :)
right now we don't have PCM devices or substreams notion. The DSP driver registers the compressed_ops (not pcm) with framework and we create the device nodes. framework would call them based on state and file_ops called.
From what I read in rawmidi and your suggestion about PCM devices, I
think you are suggesting to use a single file ops only (this a single minor number (or two, including capture) would suffice instead of a range, right? Any suggestion of which number to use? (well i followed the usually convention of PCM for minor numbers, although I cannot envision a device with multiple/large DSPs for audio offload)