From: Greg KH <gregkh@linuxfoundation•org>
To: Ian Munsie <imunsie@au1•ibm.com>
Cc: Michael Neuling <mikey@neuling•org>,
linuxppc-dev <linuxppc-dev@lists•ozlabs.org>,
stable@vger•kernel.org
Subject: Re: [PATCH] powerpc: Fix missing doorbell IPIs during nap power saving
Date: Mon, 29 Apr 2013 07:06:55 -0700 [thread overview]
Message-ID: <20130429140655.GA18950@kroah.com> (raw)
In-Reply-To: <1367223460-4931-1-git-send-email-imunsie@au1.ibm.com>
On Mon, Apr 29, 2013 at 06:17:40PM +1000, Ian Munsie wrote:
> From: Ian Munsie <imunsie@au1•ibm.com>
>
> If a doorbell IPI comes in while a thread is in nap power saving, the
> doorbell interrupt won't be replayed by the hardware since it is edge
> sensitive. Currently we are not replaying these interrupts in software,
> which can cause threads to miss IPIs that come in during power saving
> and eventually will result in an RCU warning from rcu_sched that it has
> detected a stalled CPU.
>
> This patch fixes the issue by testing if a doorbell caused the thread to
> come out of power saving and sets the corresponding bit in the paca to
> indicate a doorbell happened, which will then be handled by the existing
> interrupt replay code.
>
> This is not an issue with other interrupts that can wake a thread
> (external, decrementer) as they are level sensitive and will continue to
> be asserted by the hardware.
>
> Signed-off-by: Ian Munsie <imunsie@au1•ibm.com>
<formletter>
This is not the correct way to submit patches for inclusion in the
stable kernel tree. Please read Documentation/stable_kernel_rules.txt
for how to do this properly.
</formletter>
prev parent reply other threads:[~2013-04-29 14:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-29 8:17 [PATCH] powerpc: Fix missing doorbell IPIs during nap power saving Ian Munsie
2013-04-29 9:05 ` Benjamin Herrenschmidt
2013-04-29 14:06 ` Greg KH [this message]
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=20130429140655.GA18950@kroah.com \
--to=gregkh@linuxfoundation$(echo .)org \
--cc=imunsie@au1$(echo .)ibm.com \
--cc=linuxppc-dev@lists$(echo .)ozlabs.org \
--cc=mikey@neuling$(echo .)org \
--cc=stable@vger$(echo .)kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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