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From: Andrew Morton <akpm@osdl.org>
To: ebiederm@xmission.com (Eric W. Biederman)
Cc: Martin Lorenz <martin@lorenz.eu.org>,
	Jesse Brandeburg <jesse.brandeburg@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: Re: un/shared IRQ problem (was: Re: 2.6.18 - another DWARF2)
Date: Thu, 19 Oct 2006 10:14:11 -0700	[thread overview]
Message-ID: <20061019101411.f2466b2e.akpm@osdl.org> (raw)
In-Reply-To: <m1mz7s5plh.fsf@ebiederm.dsl.xmission.com>

On Thu, 19 Oct 2006 08:48:10 -0600
ebiederm@xmission.com (Eric W. Biederman) wrote:

> >
> > There are already three interrupt sources on 201, so they are all happy to
> > share.
> >
> > It's e1000.  Jesse, you fibbed ;)
> >
> > static int e1000_request_irq(struct e1000_adapter *adapter)
> > {
> > 	...
> > 	if (adapter->have_msi)
> > 		flags &= ~IRQF_SHARED;
> 
> Well MSI irqs can't be shared, as they are edged triggered.
> Is the e1000 really trying to use irq 201?   That would indicate
> a logic failure in the msi irq allocator.  It should never allocate
> an inuse irq.

It's gone very bad.  See 
http://www.lorenz.eu.org/~mlo/kernel/dmesg_2.6.18-ie-la-tp-41.5+0813.boot
http://www.lorenz.eu.org/~mlo/kernel/dmesg_2.6.18-ie-la-tp-41.5+0813.out

> I have to ask what is the state in 2.6.19-rc2? I'm wondering if
> my turning of the msi irq allocator inside out has fixed this problem.

Martin, please try  CONFIG_PCI_MSI=n.  I'd expect that to fix it (it always does)

> Does this situation work if MSI is disabled, in 2.6.18?
> 
> The backwards msi irq allocator in 2.6.18 is so convoluted it may have
> a corner case where it fails, and that is triggering this mess.
> 
> If 2.6.19 works with MSI's enabled and 2.6.18 works with MSI disabled
> I'm inclined to say I have done all that is reasonable.

oh, we haven't tried 2.6.19-rc2 yet?   Please do that, with CONFIG_PCI_MSI=y.

  reply	other threads:[~2006-10-19 17:14 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-10-17  6:37 2.6.18 - another DWARF2 Martin Lorenz
2006-10-17 18:52 ` Jesse Brandeburg
2006-10-18  6:34   ` un/shared IRQ problem (was: Re: 2.6.18 - another DWARF2) Martin Lorenz
2006-10-19  6:26     ` Andrew Morton
2006-10-19  6:39       ` Martin Lorenz
2006-10-19  7:01         ` Andrew Morton
2006-10-19 14:48           ` Eric W. Biederman
2006-10-19 17:14             ` Andrew Morton [this message]
2006-10-20  8:37               ` Martin Lorenz
2006-10-20  8:47                 ` Andrew Morton
2006-10-20  9:17                   ` Martin Lorenz

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