RE: Re: [ntdev] Advice sought: IOCTL or better for WDM Audio?

Please, if you’ve something meaningful to add to the knowledge gathering exercise, then do chime in. I find it helps to read posts in context too …

From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of Marion Bond
Sent: 25 April 2015 01:51
To: Windows System Software Devs Interest List
Subject: [ntdev] Re: [ntdev] Advice sought: IOCTL or better for WDM Audio?

If you have everything perfectly clear, then why are you seeking our advise?

Shoes can be used to hammer nails, but often hammers work better. If you already know which is which for your problem, then why ask?

Sent from Surface Pro

From: jerry evans mailto:xxxxx
Sent: ‎Friday‎, ‎April‎ ‎24‎, ‎2015 ‎2‎:‎31‎ ‎PM
To: Windows System Software Devs Interest List mailto:xxxxx

Hmm.

>
> It is possible to do socket I/O from the kernel. I’m not saying that’s
> the RIGHT solution; as a rule, I always argue that processing should
> never be in the kernel unless there is no other choice.

Indeed. I’ve already made this perfectly clear.

>
> Either a KS property interface or an ioctl interface can be made to
> work. MSVAD already handles standard audio KS properties, and you
> should be able to add a custom set. I know some people who are
> unfamiliar with KS end up deciding it’s easier to hook the ioctl
> interface directly.
>

Does have 2 ‘wave’ sub devices help? I am unclear as to how this affects
exclusive mode: can a second application open the ‘wave2’ device

Wondering if simpler to have a second IOCtl driver. Have the 2 drivers share
a suitable kernel mode queue for data transfer. As per
http://www.osronline.com/article.cfm?id=177 for example.

>
> I disagree. You were proposing to write a custom driver for audio
> hardware. That’s a hell of a lot of work, and unless your requirements
> truly cannot be met by an in-the-box solution, you should want to avoid
it.

No. Absolutely not. I made this perfectly clear from the get-go.

Virtual audio: built on an existing (and very long standing) Microsoft
sample, adding as little kernel mode code as possible.

>
> I’m not asking for details. I’m asking for generalities. When someone
> asks about doing something unusual, it is perfectly reasonable for us to
> explore whether the need really demands an unusual approach. Many
> people have wasted many man-months developing delicate solutions for
> problems that could have been solved much more easily.

Sorry, but no, that is simply a ‘conclusion’ based on a series of incorrect
inferences.

As for suggesting loopback modes and VAC as potential ‘solutions’ well …

BR.


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For our schedule of WDF, WDM, debugging and other seminars visit:
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To unsubscribe, visit the List Server section of OSR Online at http://www.osronline.com/page.cfm?name=ListServer</mailto:xxxxx></mailto:xxxxx>