linux-kernel - Re: [PATCH v2] pinctrl: queue GPIO operations instead of defering

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 for Android: free password hash cracker in your pocket

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

Date:	Thu, 22 Aug 2013 01:04:23 +0200
From:	Linus Walleij <linus.walleij@...aro.org>
To:	Stephen Warren <swarren@...dotorg.org>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Stephen Warren <swarren@...dia.com>,
	Haojian Zhuang <haojian.zhuang@...aro.org>,
	Lars Poeschel <poeschel@...onage.de>,
	Javier Martinez Canillas <javier.martinez@...labora.co.uk>,
	"linux-next@...r.kernel.org" <linux-next@...r.kernel.org>,
	"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>
Subject: Re: [PATCH v2] pinctrl: queue GPIO operations instead of defering

On Wed, Aug 21, 2013 at 7:45 PM, Stephen Warren <swarren@...dotorg.org> wrote:
> On 08/19/2013 01:21 PM, Stephen Warren wrote:
>> On 08/17/2013 08:56 AM, Linus Walleij wrote:
>>> We currently defer probing of the caller if a pinctrl GPIO
>>> request or direction setting comes in before the range mapping
>>> a certain GPIO to a certain pin controller is available.
>>>
>>> This can end up with a circular dependency: the GPIO driver
>>> needs the pin controller to be ready and the pin controller
>>> need the GPIO driver to be ready. This also happens if
>>> pin controllers and GPIO controllers compiled as modules
>>> are inserted in a certain order.
>>>
>>> To break this circular dependence, queue any GPIO
>>> operations coming to the framework until the range is ready,
>>> instead of deferring the probe of the caller.
>>
>> I just noticed that next-20130819 is failing on the Tegra114 Dalmore
>> board because of this patch. The kernel log is below. Reverting this
>> patch solves the problem
>
> Linus, any thoughts here?

None whatsoever, but logically it should be that your pinctrl+GPIO
driver pair depends on the GPIO driver coming first and having it's probing
deferred.

I'll rip out that patch for the time being...

Yours,
Linus Walleij
--
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/