linux-kernel - Re: [PATCH] Input: twl4030 power button: don't lose presses on resume

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20120425050919.GB27843@core.coreip.homeip.net>
Date:	Tue, 24 Apr 2012 22:09:19 -0700
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	NeilBrown <neilb@...e.de>
Cc:	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Input: twl4030 power button: don't lose presses on resume

Hi Neil,

On Wed, Apr 25, 2012 at 12:21:39PM +1000, NeilBrown wrote:
> 
> If we press and release the power button before the press interrupt is
> handled - as can happen on resume - we lose the press event so the
> release event is ignored and we don't know what happened to cause the
> wakeup.

What kind of latency do you observe?

> 
> So make sure that each interrupt handled does generate an event.
> Because twl4030 queues interrupt events we will see two interrupts
> for a press-release even if we handle the first one later.  This means
> that such a sequence will be reported as two button presses.  This
> is unfortunate but is better than no button presses.
> Possibly we could set the PENDDIS_MASK to disable queuing of
> interrupts, but that might adversely affect other interrupt sources.
>

It looks like we'd have to modify every driver to ensure consistent
behavior as we do not have any guarantees on how long resume takes.
Maybe this is something that input core needs to implement?

Thanks.


-- 
Dmitry
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/