[alsa-devel] UCM representation questions

Liam Girdwood lrg at ti.com
Fri May 27 11:20:23 CEST 2011

On 27/05/11 02:31, Mark Brown wrote:
> On Thu, May 26, 2011 at 10:13:21AM -0700, Stephen Warren wrote:
>> My thought process here was that conflicting devices are probably less
>> common than non-conflicting devices. At least, it seems like that'd be
>> the default assumption of someone writing a UCM file. So, if we list
>> ConflictingDevice(s), then that would often map to an empty list, and
>> you could eliminate the section. If we had to list all compatible
>> devices, by default you'd have to list every device in the UCM verb in
>> almost all cases. That seems like more work.
>> Plus, adding an optional ConflictingDevice list maintains backwards
>> Compatibility with any existing UCM files, whereas adding a mandatory
>> SupportedDevice list doesn't.
> I tend to agree with this - the usual case is that you can have as many
> devices as you like running, the reason for restricting things is more
> normally usefulness rather than physical possibility.
>> I wonder if allowing all lists of devices to be either inclusive
>> SupportedDevice or exclusive ConflictingDevice makes sense, with the
>> default being ConflictingDevice being empty, and SupportedDevice being
>> the entire set of devices? Seems more complex, but probably still
>> workable.
> That makes sense too - if either directive is used we require an
> explicit list, otherwise we assume everything is compatible.

Ok, sounds fine to me too. I just wanted to make sure we had explored both options here.



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