From: Anton Vorontsov <avorontsov@ru.mvista.com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: linux-kernel@vger.kernel.org, David Vrabel <david.vrabel@csr.com>,
Greg Kroah-Hartman <gregkh@suse.de>,
David Brownell <dbrownell@users.sourceforge.net>,
Grant Likely <grant.likely@secretlab.ca>,
Kumar Gala <galak@kernel.crashing.org>,
Andrew Morton <akpm@linux-foundation.org>,
spi-devel-general@lists.sourceforge.net,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 6/7] spi/mpc8xxx: don't check platform_get_irq's return value against zero
Date: Wed, 16 Dec 2009 21:20:34 +0300 [thread overview]
Message-ID: <20091216182034.GA7590@oksana.dev.rtsoft.ru> (raw)
In-Reply-To: <20091216174904.GB26325@pengutronix.de>
On Wed, Dec 16, 2009 at 06:49:04PM +0100, Uwe Kleine-König wrote:
[...]
> > Noooooo... :-(
> >
> > Please revert 305b3228f9ff4d59f49e6d34a7034d44ee8ce2f0 instead,
> > and fix platforms to remap HWIRQ0 to something that is not VIRQ0.
> >
> > IRQ0 is invalid for everything that is outside of arch/*.
> >
> > http://lkml.org/lkml/2005/11/22/159
> > http://lkml.org/lkml/2005/11/22/213
> > http://lkml.org/lkml/2005/11/22/227
> First note that my check is safe with both variants (e.g. it does the
> right thing independent of the error being signaled by 0 or
> -ESOMETHING.)
>
> Then arch/arm/mach-pxa/devices.c has:
>
> static struct resource pxa27x_resource_ssp3[] = {
> ...
> [1] = {
> .start = IRQ_SSP3,
> .end = IRQ_SSP3,
> .flags = IORESOURCE_IRQ,
> },
> ...
> }
>
> with IRQ_SSP3 being zero (sometimes). The driver is implemented in
> arch/arm/mach-pxa/ssp.c and uses platform_get_irq.
So fix this *one* driver? Implement arm-specific platform_get_irq() as
a band-aid. Or better, implement virtual irqs <-> hardware irqs mapping
for ARM.
[...]
> I'm a bit annoyed as this is the third time[1] this month this irq0
> discussion pops up for me. I think people see that irq0 is involved
> somehow, start wailing and stop seeing the issues being fixed.
For this particular driver, there is NO issue whatsoever. It is
only used for PowerPC, which has VIRQ0 == invalid IRQ. And note
that there still could be HWIRQ0 on PowerPC, but it is *never*
mapped to VIRQ0.
[...]
> [1] one is:
> http://thread.gmane.org/gmane.linux.kernel/924739
No wonder the discussion popped up. You're adding some ugly
#ifdef stuff that adds some arch-specific knowledge to a generic
code.
Sure, there's a lot of ugly code even in the kernel/ directly, but
you have to prepare for resistance when you add more of it.
So, if you want to fix the root cause of the issue: revert the
305b3228f9ff4d59f49e6d34a7034d44ee8ce2f0, and try to improve the
ARM land, do not band-aid the whole kernel all over the place.
--
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2
next prev parent reply other threads:[~2009-12-16 18:20 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1260979809-24811-1-git-send-email-u.kleine-koenig@pengutronix.de>
[not found] ` <1260979809-24811-2-git-send-email-u.kleine-koenig@pengutronix.de>
[not found] ` <1260979809-24811-3-git-send-email-u.kleine-koenig@pengutronix.de>
[not found] ` <1260979809-24811-4-git-send-email-u.kleine-koenig@pengutronix.de>
[not found] ` <1260979809-24811-5-git-send-email-u.kleine-koenig@pengutronix.de>
2009-12-16 16:10 ` [PATCH 6/7] spi/mpc8xxx: don't check platform_get_irq's return value against zero Uwe Kleine-König
2009-12-16 16:32 ` Anton Vorontsov
2009-12-16 17:49 ` Uwe Kleine-König
2009-12-16 18:20 ` Anton Vorontsov [this message]
2009-12-16 19:18 ` Uwe Kleine-König
2009-12-16 19:37 ` Anton Vorontsov
2009-12-16 19:51 ` Anton Vorontsov
2009-12-17 13:05 ` Uwe Kleine-König
2009-12-17 16:25 ` Anton Vorontsov
2009-12-16 18:20 ` David Vrabel
2009-12-17 16:39 ` Anton Vorontsov
2009-12-19 15:13 ` [PATCH] " Uwe Kleine-König
2010-01-13 11:05 ` [RESEND PATCH 5/5] " Uwe Kleine-König
2010-01-13 11:17 ` Anton Vorontsov
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