*BSD News Article 1869


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Path: sserve!manuel!munnari.oz.au!uunet!olivea!apple!apple!netcomsv!mork!hasty
From: hasty@netcom.com (Amancio Hasty Jr)
Newsgroups: comp.unix.bsd
Subject: Re: COM driver and X11
Keywords: COM X11
Message-ID: <ac0lblj.hasty@netcom.com>
Date: 11 Jul 92 03:38:25 GMT
References: <cproto.710554678@marsh>
Organization: Netcom - Online Communication Services  (408 241-9760 guest)
Lines: 13

Some thoughts on handling ast for a com driver or any device driver.

In looking at the way that my ast delivery mechanism works
Every hardware interrupt returns through icu.s.
It is possible for icu.s to detect that an interrupt happened at a higher
level and call either a driver back or a general dispatch routines
for drivers at a lower ipl level. A simple counter may suffice to indicate
that a driver needs to be called back again.

The driver may package the information in a general circular queue
along with the routine to call to process the information.

The impact on device drivers will be minimal in my opinion.