Skip site navigation (1)Skip section navigation (2)
Date:      Tue, 26 Oct 1999 01:12:47 +0000 (GMT)
From:      Terry Lambert <tlambert@primenet.com>
To:        imp@village.org (Warner Losh)
Cc:        nate@mt.sri.com, arch@freebsd.org
Subject:   Re: Racing interrupts
Message-ID:  <199910260112.SAA21635@usr06.primenet.com>
In-Reply-To: <199910251850.MAA42106@harmony.village.org> from "Warner Losh" at Oct 25, 99 12:50:45 pm

next in thread | previous in thread | raw e-mail | index | archive | help
> Yes.  W/o explicit checks for 'am I gone' it is very hard, and where
> do you make them, and there is still a tiny race between the checking
> for am I gone and the touching of hardware.  These races can be made
> so small as to be hard to lose.  That's one reason I think that having
> some way to terminate the current thread of execution at any
> instruction with a simple callback saying, "I killed your driver
> thread, cope with the loss of hardware" is about as good as we're
> going to get.  I know that we don't have kernel threads, let alone
> driver threads so this isn't a viable option at this time, but
> conceptually that's what you'll have to do, I think.

This leaks, unless you track state, and if you track state, then
you don't need to let the driver finish doing any diddling of the
hardware, you can just arrest it at any time, with the only
exception being an extra I/O bus "settle" cycle to protect yourself.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.




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




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199910260112.SAA21635>