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Subject: Re: [PATCH 1/1] irq: Maintain user set affinity
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Yinghai Lu <yinghai@kernel.org>
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Date: Sun, 09 Nov 2008 09:17:24 +1100
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On Sat, 2008-11-08 at 14:12 -0800, Yinghai Lu wrote:
> On Tue, Nov 4, 2008 at 8:31 AM, Kumar Gala <galak@kernel.crashing.org> wrote:
> > From 819ad3ed4660f4238e053728a8b5aa93d22b13d7 Mon Sep 17 00:00:00 2001
> > From: Kumar Gala <galak@kernel.crashing.org>
> > Date: Tue, 4 Nov 2008 10:13:53 -0600
> > Subject: [PATCH 1/1] irq: Maintain user set affinity
> >
> > This addresses a regression in that if a user specified an affinity
> > for an interrupt that affinity information would get reset between
> > a request_irq(), free_irq() and request_irq() for the same irq.
> >
> > On example of this is bringing up an ethernet interface, taking
> > it down and bringing it back up again.
> >
> > Instead of always using the irq_default_affinity we use the
> > previous setting of the IRQs affinity with the assumption that
> > at boot the IRQs affinity will be set to irq_default_affinity.
> 
> why ?, the default_affinity is expected behavior...
> 
> for example: when MSI is used, second driver could get same irq if
> first driver is unloaded.

The default affinity should be set when the irq is allocated / assigned
to a device, not when it's requested.

Ben.