linux-kernel - Re: [PATCH 2/3] gpio: zynq: Fixed broken wakeup implementation

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] [day] [month] [year] [list]

Date:	Thu, 4 Sep 2014 09:45:36 -0700
From:	Sören Brinkmann <soren.brinkmann@...inx.com>
To:	Linus Walleij <linus.walleij@...aro.org>
CC:	Alexandre Courbot <gnurou@...il.com>,
	Michal Simek <michal.simek@...inx.com>,
	Harini Katakam <harinik@...inx.com>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	Lars-Peter Clausen <lars@...afoo.de>,
	Ezra Savard <ezras@...inx.com>,
	Ezra Savard <ezra.savard@...inx.com>
Subject: Re: [PATCH 2/3] gpio: zynq: Fixed broken wakeup implementation

On Thu, 2014-09-04 at 06:27PM +0200, Linus Walleij wrote:
> On Fri, Aug 29, 2014 at 7:58 PM, Soren Brinkmann
> <soren.brinkmann@...inx.com> wrote:
> 
> > From: Ezra Savard <ezra.savard@...inx.com>
> >
> > Use of unmask/mask in set_wake was an incorrect implementation. The new
> > implementation correctly sets wakeup for the gpio chip's IRQ so the gpio chip
> > will not sleep while wakeup-enabled gpio are in use.
> >
> > Signed-off-by: Ezra Savard <ezra.savard@...inx.com>
> > Reviewed-by: Soren Brinkmann <soren.brinkmann@...inx.com>
> 
> Patch applied.
> 
> However the problems seems quite generic.
> 
> Do you see this kind of error in other GPIO drivers?
> 
> IRQchip semantics always make me nervous.

Our implementation was just completely flawed. It did work with our
limited tests using the sysfs interface. But once we started with the
gpio_keys things fell apart. The set_wake did mask/unmask IRQs, which
is clearly the job of the respective mask/unmask function of a gpiochip.
After we found that, we looked at a few other drivers and designed this
following gpio-mxs.
So, the core part was to do the right thing in set_wake. Once that was
done, the runtime PM callbacks needed some realignment to determine
whether GPIO is a wakeup device or not.

So, this was really just a gpio-zynq problem, not really generic.

Thanks for applying. I'll post the gpiolib-sysfs patch on its own in a
separate submission.

	Sören
--
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/