From: Alexander Stein <alexander.stein@systec-electronic.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>,
"linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
Alexandre Courbot <acourbot@nvidia.com>,
Linux Input <linux-input@vger.kernel.org>,
Tomeu Vizoso <tomeu.vizoso@collabora.com>,
Guenter Roeck <linux@roeck-us.net>,
Bjorn Andersson <bjorn.andersson@linaro.org>
Subject: Re: [PATCH] gpiolib: handle probe deferrals better
Date: Mon, 11 Apr 2016 08:10:14 +0200 [thread overview]
Message-ID: <2011375.YUICgDcM4E@ws-stein> (raw)
In-Reply-To: <CACRpkdZYyZG9=mXdWi3bnfvOqc6LFE1FykTU-QirQOJLv=Z2=A@mail.gmail.com>
On Thursday 07 April 2016 19:09:06, Linus Walleij wrote:
> >>> 4) irq_ready access synchronization on SMP? atomic?
> >>
> >> Uhhh.... I don't even understand the question.
> >
> > in my patch the irq_ready is set from _gpiochip_irqchip_add() and
> > read from gpiod_request() without any kind of protection and those
> > two functions can be executed in parallel.
>
> Aha. Well I don't know if that is really a big problem?
> Does that really happen in practice?
I guess this is what actually happens in my case. The gpio controller has
already been registred and the companion irq chip is about to be registered.
Meanwhile gpio-keys requests a GPIO from that recently registred gpio
controller and the following gpio_to_irq or irq_request returns 0 or fails as
the irq chip has not been registred yet (without Grygorii's patch). So this
calling situation might actually happen.
Best regards,
Alexander
prev parent reply other threads:[~2016-04-11 6:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-01 11:44 [PATCH] gpiolib: handle probe deferrals better Linus Walleij
2016-04-01 12:16 ` Alexander Stein
2016-04-01 13:03 ` Linus Walleij
2016-04-01 13:42 ` Alexander Stein
2016-04-01 14:03 ` Grygorii Strashko
2016-04-01 14:35 ` Alexander Stein
2016-04-01 14:04 ` Guenter Roeck
2016-04-01 17:52 ` Bjorn Andersson
2016-04-01 12:42 ` Guenter Roeck
2016-04-01 13:28 ` Grygorii Strashko
2016-04-04 16:21 ` Grygorii Strashko
2016-04-06 13:39 ` Linus Walleij
2016-04-06 15:42 ` Grygorii Strashko
2016-04-07 17:09 ` Linus Walleij
2016-04-11 6:10 ` Alexander Stein [this message]
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