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Date:      Fri, 22 Jan 1999 00:23:11 -0500
From:      "Gary T. Corcoran" <garycor@home.com>
To:        mobile@FreeBSD.ORG
Subject:   Re: Reclaiming irqs for unsupported PCI hardware?
Message-ID:  <36A80B3F.80FA5E87@home.com>
References:  <199901220158.RAA12743@dingo.cdrom.com>

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Mike Smith wrote:

> > There is no way to guarantee that the card will not be pulled in the
> > next N microseconds.
> 
> Rrrg.  This is actually a really good point,

Indeed.

> and I can see where this leads to.
> 
>  1) DO NOT REMOVE THE CARD UNTIL YOU HAVE SHUT IT DOWN.

Windows 9x also REQUIRES this.

>  2) Poll for insertions/removals since the cards are never active in
>     either state (see point 1).

Good idea - sounds like we could free up an IRQ if I'm understanding
the situation correctly (an IRQ is used for little more than notification
of card insertion ?).  I take it that the IRQ assigned to the card itself
is a separate one - is that correct?
 
> Perhaps we're just looking at this the wrong way?  We don't try to
> detect when floppies are stupidly removed, perhaps we shouldn't try to
> do it with pccard/cardbus cards either?
> 
> Commentary?  Are we trying too hard to do something that's not worth
> the effort?

After following this thread, I've come to the conclusion that since
the PCIC hardware _is not designed_ to allow arbitrary card removal
(e.g. it doesn't auto-shutoff the IRQ line), we're trying to come up
with, at best, a workaround, for something that the user _just shouldn't
do_.  In other words, just make sure mobile users know they _must_
shutdown a card before removing it, and forget about trying to handle
stupid (or accidental) user actions.

Besides, I'd rather see work going towards enabling either multi-function
cards or Cardbus cards...   ;-)
If only there were more hours in a day...<sigh>

Gary

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