From: yangyingliang@huawei.com (Yang Yingliang)
To: linux-arm-kernel@lists.infradead.org
Subject: A gic problem about eoi
Date: Fri, 19 Feb 2016 14:39:17 +0800 [thread overview]
Message-ID: <56C6B895.6070400@huawei.com> (raw)
In-Reply-To: <20160218090033.289de1c3@arm.com>
On 2016/2/18 17:00, Marc Zyngier wrote:
> 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?
I tested this patch, it can solve the problem.
Will this patch queue to stable ?
next prev parent reply other threads:[~2016-02-19 6:39 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
2016-02-19 6:39 ` Yang Yingliang [this message]
2016-02-19 11:49 ` Marc Zyngier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=56C6B895.6070400@huawei.com \
--to=yangyingliang@huawei.com \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).