Date: Sun, 02 Feb 1997 11:35:43 -0500 From: Bakul Shah <bakul@torrentnet.com> To: phk@freebsd.org Cc: current@freebsd.org Subject: Re: device driver open semantics... Message-ID: <199702021635.LAA21764@chai.plexuscom.com> In-Reply-To: Your message of "Sat, 01 Feb 1997 13:31:40 %2B0100." <3050.854800300@critter.dk.tfs.com>
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> Comments ? > > I realize that changing this behaviour in general would > probably surprise most if not all of our device-drivers, > So we're probably talking about a per-driver flag or possibly > a different open/close entry point in the [cb]devsw structure. > > Preferences ? > > Objections ? Most device drivers depend on a close() being the final close. Any change in this semantics must provide a *significant* benefit to all -- not just fix a few esoteric bugs. Adding more entry points would also further complicate the interface. Perhaps the bugs Bruce mentioned (+ things that make you dissatisfied with the way things work now) can be handled by passing some more state between the two layers? May be a callback function? In any case, cases where the present *observed* behavior does not cause faulty, unintended or inconsistent operation should remain _invariant_ under any changes. IMHO, of course! -- bakul
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