Message-ID: <55A15E93.8070706@linux.intel.com>
Date: Sat, 11 Jul 2015 11:21:07 -0700
From: Arjan van de Ven <arjan@linux.intel.com>
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To: Larry Finger <Larry.Finger@lwfinger.net>,
        LKML <linux-kernel@vger.kernel.org>,
        Li Aubrey <aubrey.li@linux.intel.com>, Ingo Molnar <mingo@kernel.org>
CC: Porteus Kiosk <porteus.kiosk@gmail.com>,
        Bastien Nocera <hadess@hadess.net>,
        Avi Weiss <aviw@benchmarkmerchantsolutions.com>,
        Benny Silberstein <bennys@benchmarkmerchantsolutions.com>
Subject: Re: V4.0.x fails to create /dev/rtc0 on Winbook TW100 when CONFIG_PINCTRL_BAYTRAIL
 is set, bisected to commit 7486341
References: <55A1598A.5040903@lwfinger.net>
In-Reply-To: <55A1598A.5040903@lwfinger.net>
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On 7/11/2015 10:59 AM, Larry Finger wrote:
> On a Winbook TW100 BayTrail tablet, kernel 4.0 and later do not create /dev/rtc0 when CONFIG_PINCTRL_BAYTRAIL is set in the configuration. Removing this option from the
> config creates a real-time clock; however, it is no longer possible to get the tablet to sleep using the power button. Only complete shutdown works.
>
> This problem was bisected to the following commit:

in "hardware reduced mode" (e.g. tablets) on Baytrail the RTC is not actually enabled/initialized by the firmware; talking to it may appear to work but it's really not
a good idea (and breaks things likes suspend/resume etc).


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