Re: V4.0.x fails to create /dev/rtc0 on Winbook TW100 when CONFIG_PINCTRL_BAYTRAIL is set, bisected to commit 7486341

From: Arjan van de Ven
Date: Sat Jul 11 2015 - 14:22:39 EST


On 7/11/2015 11:21 AM, Arjan van de Ven wrote:
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).

(or in other words, many of the legacy PC things are not supposed to be there)

what did you want to use rtc0 for?

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/