Path: utzoo!attcan!uunet!lll-winken!ames!oliveb!amiga!kodiak
From: kodiak@amiga.UUCP (Robert R. Burns)
Newsgroups: comp.sys.amiga.tech
Subject: Re: "IO Question" & "BUG IN AUDIO.DEVICE"
Message-ID: <3243@amiga.UUCP>
Date: 10 Jan 89 18:49:40 GMT
References: <8901092219.AA05714@postgres.Berkeley.EDU>
Reply-To: kodiak@tooter.UUCP (Robert Burns)
Organization: Commodore-Amiga Inc, Los Gatos CA
Lines: 46

A few comments:

In article ... (Matt Dillon) writes:
)But as I said, I do not know if the "need to set the ln_Type field
)to NT_MESSAGE" bug was fixed or not.  Can anybody at C-A say for sure that 
)all IO devices now set the ln_Type field properly for asynchronous requests?

1.  It is not necessary to set the ln_Type of an IO Request before performing
    XxxIO (DoIO/SendIO/BeginIO).  Any device that requires this is broken.

    a.  If a device defers a request (i.e. it returns from BeginIO before the
	command is completed), the ln_Type is set to NT_MESSAGE (or at least
	to *not* NT_REPLYMSG), and the IOF_QUICK flag is cleared in io_Flags.


2.  DoIO will write IOF_QUICK to io_Flags, SendIO will clear io_Flags.  We
    investigated changing these to only affect the IOB_QUICK bit itself.
    Unfortunately, some disk-based Commodore supplied devices counted on
    the fact that the other flags were clear, so changing the behavior of
    DoIO and SendIO would break old programs.  You must therefore use
    BeginIO to access the flags for robust audio & trackdisk use.

3.  We don't know of any devices broken in the mechanics of their IO
    execution (note: I don't claim all devices to be bug-free, just that
    XxxIO threads as expected).
    
    a.  Matt Dillon has reported a bug here in the way the audio.device
	replies commands.  I've both reviewed the source, which appears
	correct, and tried via email and phone to get more details (it
	appears that Matt is not being paid by the University of
	California -- I hope *someone's* paying him :-).  I have a hard
	time believing that it's cockpit error here -- Matt's an ace.

	I mention this because there's a general lesson here, albeit not a new
	one:  We appreciate the *work* y'all do to ferret out bugs in the
	Amiga.  Developers have always been instrumental to our efforts --
	but we often need more.  Please be as complete as you can when
	describing a problem.  Tell us whether you know the solution, and what
	it is if you do.  Be sure there's a way for us to get more
	information when we need it.  Amiga folk enjoy unique access to the
	development team, but sometimes it needs to be a two-way street.
-- 
Bob Burns, amiga!kodiak                   _
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