From: Chris Snook <csnook@redhat.com>
To: Scott Wood <scottwood@freescale.com>
Cc: LinuxPPC-dev list <linuxppc-dev@ozlabs.org>,
tglx@linutronix.de, maxk@qualcomm.com,
linux-kernel Kernel <linux-kernel@vger.kernel.org>
Subject: Re: default IRQ affinity change in v2.6.27 (breaking several SMP PPC based systems)
Date: Fri, 24 Oct 2008 14:18:19 -0400 [thread overview]
Message-ID: <4902116B.50509@redhat.com> (raw)
In-Reply-To: <4902086E.6030900@freescale.com>
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? 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.
-- Chris
next prev parent reply other threads:[~2008-10-24 18:18 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-24 12:45 default IRQ affinity change in v2.6.27 (breaking several SMP PPC based systems) Kumar Gala
2008-10-24 15:17 ` Chris Snook
2008-10-24 15:39 ` Kumar Gala
2008-10-24 16:09 ` Chris Snook
2008-10-24 16:36 ` Kumar Gala
2008-10-24 17:39 ` Scott Wood
2008-10-24 18:18 ` Chris Snook [this message]
2008-10-24 18:26 ` Scott Wood
2008-10-24 17:51 ` Chris Snook
2008-10-24 23:18 ` David Miller
2008-11-19 6:43 ` Max Krasnyansky
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=4902116B.50509@redhat.com \
--to=csnook@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@ozlabs.org \
--cc=maxk@qualcomm.com \
--cc=scottwood@freescale.com \
--cc=tglx@linutronix.de \
/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;
as well as URLs for NNTP newsgroup(s).