Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 22 Jan 1999 11:30:31 -0800
From:      Mike Smith <mike@smith.net.au>
To:        Nate Williams <nate@mt.sri.com>
Cc:        "Gary T. Corcoran" <garycor@home.com>, mobile@FreeBSD.ORG
Subject:   Re: Reclaiming irqs for unsupported PCI hardware? 
Message-ID:  <199901221930.LAA00927@dingo.cdrom.com>
In-Reply-To: Your message of "Fri, 22 Jan 1999 10:39:42 MST." <199901221739.KAA21533@mt.sri.com> 

next in thread | previous in thread | raw e-mail | index | archive | help
> > > 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)
> 
> Sure it does.  IRQ's are no longer generated on that piece of hardware,
> but it's possible that the IRQ routine was in the middle of processing
> the previous (valid) IRQ that was generated 'just prior' to the removal.

Uh, it's also possible for the removal itself to generate an interrupt 
- I had this 100% repeatable on the Sharp I used to use.

> > we're trying to come up
> > with, at best, a workaround, for something that the user _just shouldn't
> > do_.
> 
> What users shouldn't do and what they actually do are too different
> things.  'But it works in Linux/Win95' is the response you'll get when
> you explain to them why they shouldn't yank their 'active' cards.
> 
> (Although, as I understand it, Win98 no longer allows this and locks up
> the computer, unlike Win95.  *Most* cards can be yanked under '95, but
> some can't.)

The observation so far has been that Windows will lock up if you yank a
card on a machine that uses polling.  I'm thinking now that we'd be
better off taking the hard line - the card must be shut off in software
before removing.

> > 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.
> 
> The use of the IRQ makes it less painful *IF* the user yanks their
> card.  Is it worth making it easier?  I don't know.

That's it in a nutshell.

-- 
\\  Sometimes you're ahead,       \\  Mike Smith
\\  sometimes you're behind.      \\  mike@smith.net.au
\\  The race is long, and in the  \\  msmith@freebsd.org
\\  end it's only with yourself.  \\  msmith@cdrom.com



To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-mobile" in the body of the message



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199901221930.LAA00927>