From: ebiederm@xmission.com (Eric W. Biederman)
To: Joe Korty <joe.korty@ccur.com>
Cc: "venkatesh.pallipadi\@intel.com" <venkatesh.pallipadi@intel.com>,
"mingo\@elte.hu" <mingo@elte.hu>,
"linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] clear irq pending when bypassing it
Date: Thu, 30 Apr 2009 11:43:55 -0700 [thread overview]
Message-ID: <m11vrayob8.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <20090430180011.GB28139@tsunami.ccur.com> (Joe Korty's message of "Thu\, 30 Apr 2009 14\:00\:12 -0400")
Joe Korty <joe.korty@ccur.com> writes:
> On Thu, Apr 30, 2009 at 12:49:39PM -0400, Eric W. Biederman wrote:
>> Joe Korty <jak@typhoon.ccur.com> writes:
>>
>> > IRQ_MOVE_PENDING must be cleared whenever it is bypassed.
>> >
>> > Otherwise, we risk an old, pending affinity change
>> > overtaking and erasing a more recent affinity change that
>> > had been directly applied (eg, IRQ_MOVE_PCNTXT mode).
>>
>> When can this happen?
>
> Probably doesn't happen. AFAIK, each IRQ is either fully MSI
> or non-MSI. The MSI IRQs will always use IRQ_MOVE_PCNTXT and
> the non-MSI's will never use IRQ_MOVE_PCNTXT. Thus no collision.
>
> It could only happen if it was possible for a MSI and non-MSI
> device to share an IRQ.
Ok. I thought you might have seen something.
It doesn't happen and it can't happen, making your patch wrong.
Eric
prev parent reply other threads:[~2009-04-30 18:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20090430161506.GA2636@typhoon.ccur.com>
2009-04-30 16:49 ` [PATCH] clear irq pending when bypassing it Eric W. Biederman
2009-04-30 18:00 ` Joe Korty
2009-04-30 18:43 ` Eric W. Biederman [this message]
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