From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Linus Torvalds <torvalds@osdl.org>
Cc: viro@parcelfarce.linux.theplanet.co.uk,
Linux Kernel list <linux-kernel@vger.kernel.org>,
Marcelo Tosatti <marcelo.tosatti@cyclades.com>,
Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Subject: Re: [RFC] disable_irq()/enable_irq() semantics and ide-probe.c
Date: Thu, 09 Oct 2003 10:07:15 +0200 [thread overview]
Message-ID: <1065686834.7081.83.camel@gaston> (raw)
In-Reply-To: <Pine.LNX.4.44.0310081947330.19510-100000@home.osdl.org>
> >
> > ObOtherFun: There's another bogosity in quoted ide-probe.c code, according
> > to dwmw2 - he says that there are PCI IDE cards that get IRQ 0, so the
> > test for hwif->irq is b0rken. We probably should stop overloading
> > ->irq == 0 for "none given", but I'm not sure that we *have* a value
> > that would never be used as an IRQ number on all platforms...
>
> The BIOS defines irq 0 in the PCI config space to be "no irq" as far as I
> know, and on all PC platforms I've ever heard of it's not a usable irq for
> generic PCI devices (it's wired to the timer thing).
>
> All PCI routing chipsets I know about also make "irq0" mean "disabled".
>
> Which is not to say that a badly configured setup might not do it, but it
> really sounds fundamentally broken.
Well, irq 0 is a perfectly valid IRQ on a number of non-x86 platforms,
some embedded platforms for example, and iirc, the Apple G5 even has
the serverworks IDE on IRQ 0 ;)
That's why we have defined IRQ_NONE a while ago (this was in 2.4, I
don'tk now if that made the trip to 2.6, I'm away from my sources
at the moment).
Ben.
next prev parent reply other threads:[~2003-10-09 8:09 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-10-09 2:00 [RFC] disable_irq()/enable_irq() semantics and ide-probe.c viro
2003-10-09 2:29 ` Linus Torvalds
2003-10-09 2:43 ` viro
2003-10-09 2:53 ` Linus Torvalds
2003-10-09 8:03 ` Russell King
2003-10-09 22:46 ` Zwane Mwaikambo
2003-10-09 8:07 ` Benjamin Herrenschmidt [this message]
2003-10-09 15:46 ` viro
2003-10-09 16:01 ` Linus Torvalds
2003-10-09 17:46 ` viro
2003-10-09 18:03 ` Linus Torvalds
2003-10-09 18:27 ` viro
2003-10-09 19:05 ` Linus Torvalds
2003-10-15 17:14 ` Anton Blanchard
2003-10-17 9:19 ` Russell King
2003-10-17 10:32 ` Benjamin Herrenschmidt
2003-10-09 12:55 ` Roman Zippel
-- strict thread matches above, loose matches on Subject: below --
2003-10-09 16:10 Manfred Spraul
2003-10-09 16:38 ` Jeff Garzik
2003-10-09 16:57 ` Benjamin Herrenschmidt
2003-10-09 17:03 ` Jeff Garzik
2003-10-09 17:07 ` Benjamin Herrenschmidt
2003-10-09 17:16 ` Jeff Garzik
2003-10-09 17:29 ` Linus Torvalds
2003-10-09 17:52 ` Jeff Garzik
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1065686834.7081.83.camel@gaston \
--to=benh@kernel.crashing.org \
--cc=B.Zolnierkiewicz@elka.pw.edu.pl \
--cc=linux-kernel@vger.kernel.org \
--cc=marcelo.tosatti@cyclades.com \
--cc=torvalds@osdl.org \
--cc=viro@parcelfarce.linux.theplanet.co.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox