linux-kernel - Re: [RFC][PATCH] rtc: rtc-pl031: Set wakeup flag prior to registering rtcdev

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Message-ID: <CACRpkdY-6eUWG6CWpBMi=yy2m158xwsF4h48yqZNzvBe_LW14Q@mail.gmail.com>
Date:	Wed, 18 Sep 2013 13:30:49 +0200
From:	Linus Walleij <linus.walleij@...aro.org>
To:	John Stultz <john.stultz@...aro.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Alessandro Zummo <a.zummo@...ertech.it>,
	"Jon Medhurst (Tixy)" <tixy@...aro.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [RFC][PATCH] rtc: rtc-pl031: Set wakeup flag prior to registering rtcdev

On Tue, Sep 17, 2013 at 8:29 PM, John Stultz <john.stultz@...aro.org> wrote:

> In some recent testing, I noticed the CLOCK_REALTIME_ALARM clockid
> wasn't functioning on my vexpress qemu environment. Looking into it
> I noticed the pl031 rtc driver doesn't set the wakeup flag on the
> device until after registering the device with the RTC subsystem.
>
> This causes the alarmtimer subsystem to not see the pl031 driver
> as a valid backing device, and that resuls in alarm clockids
> getting ENOTSUPP errors.
>
> Thus be sure to set the wakeup flag on the device prior to
> registering the rtcdev so the pl031 rtc driver can be used as
> the backing alarmtimer device.
>
> Let me know if you have any feedback or objections to this.
> If it looks ok, I'll queue it for 3.13. I suspect there
> may be other RTC drivers with the same problem.
>
> Cc: Linus Walleij <linus.walleij@...aro.org>
> Cc: Alessandro Zummo <a.zummo@...ertech.it>
> Cc: "Jon Medhurst (Tixy)" <tixy@...aro.org>
> Cc: linux-arm-kernel@...ts.infradead.org
> Signed-off-by: John Stultz <john.stultz@...aro.org>

Makes perfect sense. I have only tested the driver from regular
userspace using ioctl()s. Is these a simple way to test
an alarmtimer on a barebones system?

Acked-by: Linus Walleij <linus.walleij@...aro.org>

Are you sure this should not be for -rc:s and stable?

Yours,
Linus Walleij
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