lkml.org 
[lkml]   [2008]   [Oct]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: default IRQ affinity change in v2.6.27 (breaking several SMP PPC based systems)
Chris Snook wrote:
> Scott Wood wrote:
>> Kumar Gala wrote:
>>> So why not just have x86 startup code set irq_default_affinity =
>>> CPU_MASK_ALL than?
>>
>> That doesn't really solve the problem, as a user could still manually
>> set an invalid affinity. The MPIC driver should reduce the affinity
>> itself to what the hardware can handle.
>
> Does the MPIC code actually allow that to happen?

As far as I can tell, though I haven't tested it.

> I can't quite tell, but I noticed this:
>
> [csnook@bernoulli sysdev]$ fgrep '#ifdef CONFIG_' mpic.c | sort -u
> #ifdef CONFIG_IRQ_ALL_CPUS
> #ifdef CONFIG_MPIC_BROKEN_REGREAD
> #ifdef CONFIG_MPIC_U3_HT_IRQS
> #ifdef CONFIG_MPIC_WEIRD
> #ifdef CONFIG_PCI_MSI
> #ifdef CONFIG_PM
> #ifdef CONFIG_PPC32 /* XXX for now */
> #ifdef CONFIG_PPC_DCR
> #ifdef CONFIG_SMP
>
> Do any of those config options (or combinations thereof) imply an MPIC
> that can't handle an IRQ masked to multiple CPUs? If so, this can be
> fixed rather easily at build time, without having to muck around with
> arch-specific initialization code.

I don't think so, and in any case it should be detected at runtime from
the device tree.

-Scott



\
 
 \ /
  Last update: 2008-10-24 20:29    [W:0.029 / U:1.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site