From: Nicolas Pitre <nicolas.pitre@linaro.org>
To: Dave Martin <dave.martin@linaro.org>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Anton Vorontsov <cbouatmailru@gmail.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Andrew Morton <akpm@linux-foundation.org>,
devicetree-discuss@lists.ozlabs.org,
LKML <linux-kernel@vger.kernel.org>,
linux-ide@vger.kernel.org, Randy Dunlap <rdunlap@xenotime.net>,
linux-next@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Jeff Garzik <jgarzik@redhat.com>, Pawel Moll <pawel.moll@arm.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] ata: Don't use NO_IRQ in pata_of_platform driver
Date: Mon, 5 Dec 2011 13:18:30 -0500 (EST) [thread overview]
Message-ID: <alpine.LFD.2.02.1112051310150.2357@xanadu.home> (raw)
In-Reply-To: <20111205180253.GB29812@localhost.localdomain>
On Mon, 5 Dec 2011, Dave Martin wrote:
> On Mon, Dec 05, 2011 at 12:40:16PM -0500, Nicolas Pitre wrote:
> > On Mon, 5 Dec 2011, Dave Martin wrote:
> > > On Sat, Dec 03, 2011 at 10:12:53AM +1100, Benjamin Herrenschmidt wrote:
> > > > On Fri, 2011-12-02 at 11:28 -0800, Linus Torvalds wrote:
> > > > > Don't *change* NO_IRQ to zero (that whole #define is broken - leave it
> > > > > around as a marker of brokenness), just start removing it from all the
> > > > > ARM drivers that use the OF infrastructure. Which is presumably not
> > > > > all that many yet.
> > > > >
> > > > > So whenever you find breakage, the fix now is to just remove NO_IRQ
> > > > > tests, and replace them with "!irq".
> > > >
> > >
> > > Russell, do you know whether it would make sense to set a timeline for
> > > removing NO_IRQ from ARM platforms and migrating to 0 for the no-interrupt
> > > case? I'm assuming that this mainly involves migrating existing hard-wired
> > > code that deals with interrupt numbers to use irq domains.
> >
> > How many drivers do use IRQ #0 to start with? We might discover that in
> > practice there is only a very few cases where this is an issue if 0
> > would mean no IRQ.
>
> The total number of files referring to NO_IRQ is not that huge:
>
> arch/arm/ 188 matches in 39 files
> drivers/ 174 matches in 84 files
>
> Unfortunately, NO_IRQ is often not spelled "NO_IRQ". It looks like the assumption
> "irq < 0 === no irq" may be quite a lot more widespread than "NO_IRQ === no irq".
> Since there's no specific thing we can grep for (and simply due to volume)
> finding all such instances may be quite a bit harder.
[...]
ARgh.
My point was about current actual usage of the IRQ numbered 0 which
probably prompted the introduction of NO_IRQ in the first place. What I
was saying is that the number of occurrences where IRQ #0 is currently
used into drivers that would get confused if 0 would mean no IRQ is
probably quite small.
But as you illustrated, there is a large number of drivers that already
assume no IRQ is < 0, even if they don't use any IRQ #0 themselves.
That is a much bigger problem to fix.
Nicolas
next prev parent reply other threads:[~2011-12-05 18:18 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-11 9:11 linux-next: Tree for Oct 11 Stephen Rothwell
2011-10-11 18:26 ` [PATCH -next] x86: perf_event_intel.c needs export.h Randy Dunlap
2011-10-11 18:49 ` linux-next: Tree for Oct 11 (mmc) Randy Dunlap
2011-10-11 19:31 ` mmc core broken dependency on CONFIG_BLOCK (Was: linux-next: Tree for Oct 11 (mmc)) Andrei Warkentin
2011-10-11 21:59 ` Randy Dunlap
2011-10-11 23:20 ` NamJae Jeon
2011-10-11 23:48 ` Andrei Warkentin
2011-10-12 0:16 ` NamJae Jeon
2011-10-12 0:50 ` Andrei Warkentin
2011-10-12 1:55 ` NamJae Jeon
2011-10-11 19:15 ` [PATCH -next] jbd2: fix build when CONFIG_BUG is not enabled Randy Dunlap
2011-10-27 8:06 ` Ted Ts'o
2011-10-11 19:26 ` linux-next: Tree for Oct 11 (mfd/intel_msic.c) Randy Dunlap
2011-10-11 19:32 ` linux-next: Tree for Oct 11 (gpio regulator) Randy Dunlap
2011-10-11 20:22 ` Heiko Stübner
2011-10-11 20:37 ` linux-next: Tree for Oct 11 (ata/pata_of_platform.c) Randy Dunlap
2011-10-14 17:58 ` Randy Dunlap
2011-11-10 13:57 ` Ingo Molnar
2011-11-10 14:25 ` Alan Cox
2011-11-10 15:18 ` [PATCH] ata: Fix build error in pata_of_platform (NO_IRQ usage) Anton Vorontsov
2011-11-10 15:25 ` [PATCH 1/2] of/irq: Get rid of NO_IRQ usage Anton Vorontsov
2011-12-06 21:22 ` Rob Herring
2011-12-06 21:25 ` Linus Torvalds
2011-12-06 23:16 ` [PATCH v3] " Anton Vorontsov
2011-12-07 3:51 ` Rob Herring
[not found] ` <20111206231626.GA31683-wnGakbxT3iijyJ0x5qLZdcN33GVbZNy3@public.gmane.org>
2011-12-07 9:52 ` Wolfram Sang
2011-11-10 15:26 ` [PATCH 2/2] ata: Don't use NO_IRQ in pata_of_platform driver Anton Vorontsov
2011-11-10 15:38 ` Alan Cox
2011-11-10 16:28 ` [PATCH] " Anton Vorontsov
2011-11-10 20:34 ` Jeff Garzik
2011-12-02 19:19 ` Dave Martin
2011-12-02 22:34 ` Anton Vorontsov
2011-12-02 22:40 ` Anton Vorontsov
2011-12-02 22:46 ` Anton Vorontsov
2011-12-02 22:40 ` Linus Torvalds
2011-12-02 23:18 ` [PATCH v2] of/irq: Get rid of NO_IRQ usage Anton Vorontsov
2011-12-02 23:22 ` [PATCH] ata: Don't use NO_IRQ in pata_of_platform driver Alan Cox
2011-12-03 18:56 ` Geert Uytterhoeven
2011-12-02 19:26 ` Dave Martin
2011-12-02 19:28 ` Linus Torvalds
2011-12-02 23:12 ` Benjamin Herrenschmidt
2011-12-05 16:11 ` Dave Martin
2011-12-05 17:40 ` Nicolas Pitre
2011-12-05 18:02 ` Dave Martin
2011-12-05 18:15 ` Geert Uytterhoeven
2011-12-05 18:18 ` Nicolas Pitre [this message]
[not found] ` <alpine.LFD.2.02.1112051310150.2357-QuJgVwGFrdf/9pzu0YdTqQ@public.gmane.org>
2011-12-05 18:45 ` Alan Cox
2011-12-05 19:19 ` James Bottomley
2011-12-06 6:13 ` Jean-Christophe PLAGNIOL-VILLARD
[not found] ` <20111206061321.GH9192-RQcB7r2h9QmfDR2tN2SG5Ni2O/JbrIOy@public.gmane.org>
2011-12-06 11:34 ` Alan Cox
2011-12-05 19:16 ` Rob Herring
2011-12-05 20:21 ` Anton Vorontsov
2011-12-05 20:47 ` Rob Herring
[not found] ` <4EDD2DE1.1050606-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2011-12-05 20:53 ` Alan Cox
2011-12-06 9:30 ` Dave Martin
[not found] ` <20111206093000.GA2274-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2011-12-06 10:34 ` Alan Cox
2011-12-06 10:55 ` Russell King - ARM Linux
2011-12-05 19:26 ` Dave Martin
2011-12-05 19:49 ` Nicolas Pitre
2011-12-06 9:37 ` Dave Martin
[not found] ` <20111206093709.GB2274-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2011-12-06 10:46 ` Russell King - ARM Linux
2011-12-06 11:00 ` Geert Uytterhoeven
2011-12-06 11:03 ` Russell King - ARM Linux
2011-12-06 11:10 ` Alan Cox
2011-12-06 11:05 ` Alan Cox
[not found] ` <20111206110554.53bddd14-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org>
2011-12-06 11:25 ` Russell King - ARM Linux
2011-12-06 12:11 ` Alan Cox
2011-12-06 11:37 ` Dave Martin
2011-12-06 11:49 ` Russell King - ARM Linux
2011-12-06 13:25 ` Dave Martin
2011-12-06 19:56 ` Rob Herring
2011-12-06 19:20 ` Linus Torvalds
2011-12-06 20:00 ` Russell King - ARM Linux
[not found] ` <CA+55aFwZBr+3_S9kU-+m8zN8iwOvn2miuuAy-zt7sUjW_+abBg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2011-12-06 20:59 ` Uwe Kleine-König
2011-12-06 19:11 ` Nicolas Pitre
[not found] ` <20111205161157.GA27550-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2011-12-05 17:41 ` Alan Cox
2011-11-10 15:35 ` [PATCH] ata: Fix build error in pata_of_platform (NO_IRQ usage) Alan Cox
2011-11-10 18:18 ` linux-next: Tree for Oct 11 (ata/pata_of_platform.c) Jeff Garzik
[not found] ` <20111011201127.455df266dcbffb1d621f8576-3FnU+UHB4dNDw9hX6IcOSA@public.gmane.org>
2011-10-11 20:45 ` linux-next: Tree for Oct 11 (iio/resolver) Randy Dunlap
[not found] ` <4E94AADA.4080204-/UHa2rfvQTnk1uMJSBkQmQ@public.gmane.org>
2011-10-12 8:58 ` Jonathan Cameron
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