lkml.org 
[lkml]   [2009]   [Dec]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 6/7] spi/mpc8xxx: don't check platform_get_irq's return value against zero
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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2009-12-16 19:23    [W:0.097 / U:0.052 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site