linux-kernel - Re: [PATCH] rtc-omap: Fix initialization of control register

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Message-ID: <4E312FF5.1080007@emlix.com>
Date:	Thu, 28 Jul 2011 11:46:29 +0200
From:	Daniel Glöckner <dg@...ix.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	Alessandro Zummo <a.zummo@...ertech.it>,
	"George G. Davis" <gdavis@...sta.com>, rtc-linux@...glegroups.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] rtc-omap: Fix initialization of control register

On 07/27/2011 11:19 PM, Andrew Morton wrote:
> On Mon, 11 Jul 2011 12:57:46 +0200
> Daniel Gl__ckner <dg@...ix.com> wrote:
> 
>> As the comment explains, the intention of the code is to clear the
>> OMAP_RTC_CTRL_MODE_12_24 bit, but instead it only clears the
>> OMAP_RTC_CTRL_SPLIT and OMAP_RTC_CTRL_AUTO_COMP bits, which should be
>> kept. OMAP_RTC_CTRL_DISABLE, OMAP_RTC_CTRL_SET_32_COUNTER,
>> OMAP_RTC_CTRL_TEST, and OMAP_RTC_CTRL_ROUND_30S are also better off
>> being cleared.

> What were the user-visible effects of the bug?

The contents of the control register is undefined after a complete power
loss. On our board the RTC has been observed to sometimes power up with the
OMAP_RTC_CTRL_SET_32_COUNTER bit being set, which stops the clock.

  Daniel

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