From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: A gic problem about eoi
Date: Thu, 18 Feb 2016 09:00:33 +0000 [thread overview]
Message-ID: <20160218090033.289de1c3@arm.com> (raw)
In-Reply-To: <56C5500A.2060104@huawei.com>
On Thu, 18 Feb 2016 13:00:58 +0800
Yang Yingliang <yangyingliang@huawei.com> wrote:
Hi Yang,
> Hi, Marc
>
> We found if hardware clear pending and active status is slower than
> software handling, the new sgi will be merged because of hardware
> status. The new sgi will be lost.
>
> If we add a dsb instruction after gic_write_eoir(), it can avoid this
> case happening.
>
> Is it a right way to add a dsb instruction after gic_write_eoir()
> in current gic driver code ?
I suspect your problem is not so much the EOI, but that the read of
ICC_IAR1_EL1 doesn't propagate the Ack quickly enough, leading to the
transition from pending to active to still be in flux when the interrupt
is EOIed. This is where a DSB is required (and was missing until very
recently).
Does 1a1ebd5 ("irqchip/gic-v3: Make sure read from ICC_IAR1_EL1 is
visible on redestributor") solve your problem?
Thanks,
M.
--
Jazz is not dead. It just smells funny.
next prev parent reply other threads:[~2016-02-18 9:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-18 5:00 A gic problem about eoi Yang Yingliang
2016-02-18 9:00 ` Marc Zyngier [this message]
2016-02-19 6:39 ` Yang Yingliang
2016-02-19 11:49 ` Marc Zyngier
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