Re: [PATCH v3 0/5] ALSA: snd-usb: add support for DSD

[Daniel Mack <zonque@gmail.com>]

On 17.04.2013 19:01, Jussi Laako wrote:
> On 04/17/2013 02:03 PM, Daniel Mack wrote:
>> I'd like to wait for another day or so for Jussi to state his oppinion.
> 
> Looks good to me. Hopefully the necessary details about bit ordering 
> find their way to the ALSA API docs.

You volunteer for sending a patch? :)

> 
> I was left thinking about how this:
> 
>> +	if (pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
>> +		/*
>> +		 * When operating in DSD DOP mode, the size of a sample frame
>> +		 * in hardware differs from the actual physical format width
>> +		 * because we need to make room for the DOP markers.
>> +		 */
>> +		frame_bits += channels << 3;
>> +	}
> 
> relates to case where the endpoint uses 32-bit int sample format and 
> thus needs a zero pad byte for DoP...

Ok, that's a case I haven't though of yet, but we can easily extend that
logic once such a device is used by anyone. For now, this entire logic
is only relevant for one series of devices, and for that, we know the
parameters exactly.

The important thing is that we don't have to break the userspace API,
but I think we're safe here, right?


Thanks,
Daniel