* Less strict parsing - and allowing out-of-sequence triplets will make the
Win10 UAC2 driver compatible with more hardware which is already in the field.
Please create a feature request for this and ideally include an example of
hardware that would benefit from it
https://blogs.msdn.microsoft.com/matthew_van_eerde/2016/09/26/report-problems-with-logs-and-suggest-features-with-the-feedback-hub/
________________________________
From: wdmaudiodev-bounce@xxxxxxxxxxxxx <wdmaudiodev-bounce@xxxxxxxxxxxxx> on
behalf of Børge Strand-Bergesen <borge.strand@xxxxxxxxx>
Sent: Thursday, January 11, 2018 12:39:09 AM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: Support for clock source selection for USB2 Audio?
How does this tie in with sample rate triplets?
you may remember the struggles I have a few months ago with sample rate triplet
parsing. At the time I considered splitting it into two virtual clocks. Reading
this I'm glad I didn't.
The DAC I make has two physical clocks which are chosen by firmware depending
on which sample rate is requested by the driver. So the firmware only exposes
one clock to the driver. Let me know if you need code and descriptors, both are
open source in my case.
Possibly OT: Before the Win10 UAC2 driver came out, all other OSes with UAC2
allowed for very relaxed sample sample rate triplet parsing. I.e. triplets
could come in an arbitrary sequence, and available rates came out of some
sort() which followed some sort of parse(). That was the world in which our
firmware was tested and found to be solid. Less strict parsing - and allowing
out-of-sequence triplets will make the Win10 UAC2 driver compatible with more
hardware which is already in the field.
Best,
Børge
On Thu, Jan 11, 2018 at 9:14 AM, Franz Detro
<franz.detro@xxxxxxxxxxxxxxxxxxxxx<mailto:franz.detro@xxxxxxxxxxxxxxxxxxxxx>>
wrote:
KS wrote:
In USB2 Audio, it is possible for device to support multiple clock
source that can be selected through a clock selector.
I don't see that anywhere in the Audio Class specification. Where is
that described?
In Mac OS, there is a droplist in audio MIDI app that allow user to
select the desired clock source.
What choices do you see?
--
Tim Roberts, timr@xxxxxxxxx<mailto:timr@xxxxxxxxx>
Providenza & Boekelheide, Inc.
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