From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Maxim Levitsky <maximlevitsky@gmail.com>
Cc: linuxppc-dev list <linuxppc-dev@ozlabs.org>,
akpm <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Linux Kernel list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] synchronize_irq needs a barrier
Date: Sat, 20 Oct 2007 14:06:01 +1000 [thread overview]
Message-ID: <1192853161.17235.34.camel@pasglop> (raw)
In-Reply-To: <200710200510.01409.maximlevitsky@gmail.com>
> > - even when you ignore the interrupt (because the driver doesn't care,
> > it's suspending), you need to make sure the hardware gets shut up by
> > reading (or writing) the proper interrupt status register.
> I agree, but while device is powered off, its registers can't be accessed
> Thus, if I ack the IRQ every time the handler is called, I will access the
> powered off device (this is probably won't hurt a lot, but a bit incorrectly)
It will actually crash your machine on some platforms. So no, best is to
-not- ack. The masking is enough, the IRQ will go down eventually.
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Maxim Levitsky <maximlevitsky@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
akpm <akpm@linux-foundation.org>,
Linux Kernel list <linux-kernel@vger.kernel.org>,
linuxppc-dev list <linuxppc-dev@ozlabs.org>
Subject: Re: [PATCH] synchronize_irq needs a barrier
Date: Sat, 20 Oct 2007 14:06:01 +1000 [thread overview]
Message-ID: <1192853161.17235.34.camel@pasglop> (raw)
In-Reply-To: <200710200510.01409.maximlevitsky@gmail.com>
> > - even when you ignore the interrupt (because the driver doesn't care,
> > it's suspending), you need to make sure the hardware gets shut up by
> > reading (or writing) the proper interrupt status register.
> I agree, but while device is powered off, its registers can't be accessed
> Thus, if I ack the IRQ every time the handler is called, I will access the
> powered off device (this is probably won't hurt a lot, but a bit incorrectly)
It will actually crash your machine on some platforms. So no, best is to
-not- ack. The masking is enough, the IRQ will go down eventually.
Ben.
next prev parent reply other threads:[~2007-10-20 4:06 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-18 1:25 [PATCH] synchronize_irq needs a barrier Benjamin Herrenschmidt
2007-10-18 1:25 ` Benjamin Herrenschmidt
2007-10-18 1:45 ` Andrew Morton
2007-10-18 1:45 ` Andrew Morton
2007-10-18 1:55 ` Benjamin Herrenschmidt
2007-10-18 1:55 ` Benjamin Herrenschmidt
2007-10-18 2:12 ` Linus Torvalds
2007-10-18 2:12 ` Linus Torvalds
2007-10-18 2:40 ` Benjamin Herrenschmidt
2007-10-18 2:40 ` Benjamin Herrenschmidt
2007-10-18 2:57 ` Benjamin Herrenschmidt
2007-10-18 2:57 ` Benjamin Herrenschmidt
2007-10-18 14:56 ` Herbert Xu
2007-10-18 14:56 ` Herbert Xu
2007-10-18 22:05 ` Benjamin Herrenschmidt
2007-10-18 22:05 ` Benjamin Herrenschmidt
2007-10-18 22:52 ` Linus Torvalds
2007-10-18 22:52 ` Linus Torvalds
2007-10-18 23:17 ` Benjamin Herrenschmidt
2007-10-18 23:17 ` Benjamin Herrenschmidt
2007-10-18 23:39 ` Linus Torvalds
2007-10-18 23:39 ` Linus Torvalds
2007-10-18 23:52 ` Benjamin Herrenschmidt
2007-10-18 23:52 ` Benjamin Herrenschmidt
2007-10-19 2:32 ` Herbert Xu
2007-10-19 2:32 ` Herbert Xu
2007-10-19 2:52 ` Nick Piggin
2007-10-19 2:52 ` Nick Piggin
2007-10-19 3:28 ` Herbert Xu
2007-10-19 3:28 ` Herbert Xu
2007-10-19 4:49 ` Nick Piggin
2007-10-19 4:49 ` Nick Piggin
2007-10-19 2:55 ` Linus Torvalds
2007-10-19 2:55 ` Linus Torvalds
2007-10-19 3:26 ` Linus Torvalds
2007-10-19 3:26 ` Linus Torvalds
2007-10-19 4:11 ` Benjamin Herrenschmidt
2007-10-19 4:11 ` Benjamin Herrenschmidt
2007-10-19 4:26 ` Benjamin Herrenschmidt
2007-10-19 4:26 ` Benjamin Herrenschmidt
2007-10-19 5:53 ` Herbert Xu
2007-10-19 5:53 ` Herbert Xu
2007-10-19 4:20 ` Herbert Xu
2007-10-19 4:20 ` Herbert Xu
2007-10-19 4:29 ` Benjamin Herrenschmidt
2007-10-19 4:29 ` Benjamin Herrenschmidt
2007-10-19 4:35 ` Benjamin Herrenschmidt
2007-10-19 4:35 ` Benjamin Herrenschmidt
2007-10-19 4:48 ` Herbert Xu
2007-10-19 4:48 ` Herbert Xu
2007-10-19 4:58 ` Benjamin Herrenschmidt
2007-10-19 4:58 ` Benjamin Herrenschmidt
2007-10-21 21:10 ` Benjamin Herrenschmidt
2007-10-21 21:10 ` Benjamin Herrenschmidt
2007-10-23 3:26 ` [IRQ]: Fix synchronize_irq races with IRQ handler Herbert Xu
2007-10-23 3:26 ` Herbert Xu
2007-10-19 5:36 ` [NET]: Fix possible dev_deactivate race condition Herbert Xu
2007-10-19 5:36 ` Herbert Xu
2007-10-19 5:38 ` David Miller
2007-10-19 5:38 ` David Miller
2007-10-19 7:35 ` Peter Zijlstra
2007-10-19 7:35 ` Peter Zijlstra
2007-10-19 9:29 ` Herbert Xu
2007-10-19 9:29 ` Herbert Xu
2007-10-18 14:35 ` [PATCH] synchronize_irq needs a barrier Herbert Xu
2007-10-18 14:35 ` Herbert Xu
2007-10-18 21:35 ` Benjamin Herrenschmidt
2007-10-18 21:35 ` Benjamin Herrenschmidt
2007-10-20 2:02 ` Maxim Levitsky
2007-10-20 2:02 ` Maxim Levitsky
2007-10-20 2:25 ` Linus Torvalds
2007-10-20 2:25 ` Linus Torvalds
2007-10-20 3:10 ` Maxim Levitsky
2007-10-20 3:10 ` Maxim Levitsky
2007-10-20 4:06 ` Benjamin Herrenschmidt [this message]
2007-10-20 4:06 ` Benjamin Herrenschmidt
2007-10-20 4:04 ` Benjamin Herrenschmidt
2007-10-20 4:04 ` Benjamin Herrenschmidt
2007-10-20 4:09 ` Benjamin Herrenschmidt
2007-10-20 4:09 ` Benjamin Herrenschmidt
2007-10-20 3:37 ` Herbert Xu
2007-10-20 3:37 ` Herbert Xu
2007-10-20 3:56 ` Benjamin Herrenschmidt
2007-10-20 3:56 ` Benjamin Herrenschmidt
2007-10-20 4:24 ` Maxim Levitsky
2007-10-20 4:24 ` Maxim Levitsky
2007-10-20 5:04 ` Benjamin Herrenschmidt
2007-10-20 5:04 ` Benjamin Herrenschmidt
2007-10-20 5:36 ` Maxim Levitsky
2007-10-20 5:36 ` Maxim Levitsky
2007-10-20 5:46 ` Benjamin Herrenschmidt
2007-10-20 5:46 ` Benjamin Herrenschmidt
2007-10-20 6:06 ` Maxim Levitsky
2007-10-20 6:06 ` Maxim Levitsky
2007-10-20 6:13 ` Benjamin Herrenschmidt
2007-10-20 6:13 ` Benjamin Herrenschmidt
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