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Subject: Re: [PATCH] x86/hpet: fix typo from rtc cleanup
To: Arnd Bergmann <arnd@arndb.de>, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
        x86@kernel.org
References: <20160809195528.1604312-1-arnd@arndb.de>
Cc: =?UTF-8?B?VmlsbGUgU3lyasOkbMOk?= <ville.syrjala@linux.intel.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Alexandre Belloni <alexandre.belloni@free-electrons.com>,
        Alessandro Zummo <a.zummo@towertech.it>, rtc-linux@googlegroups.com,
        Borislav Petkov <bp@suse.de>, linux-kernel@vger.kernel.org
From: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Message-ID: <adba492a-ad23-1376-4383-b819e43f786e@linux.intel.com>
Date: Wed, 10 Aug 2016 11:22:46 +0300
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Hi

On 08/09/2016 10:54 PM, Arnd Bergmann wrote:
> Ville Syrjälä reports "The first time I run hwclock after rebooting
> I get this:
>
>  open("/dev/rtc", O_RDONLY)              = 3
>  ioctl(3, PHN_SET_REGS or RTC_UIE_ON, 0) = 0
>  select(4, [3], NULL, NULL, {10, 0})     = 0 (Timeout)
>  ioctl(3, PHN_NOT_OH or RTC_UIE_OFF, 0)  = 0
>  close(3)                                = 0
>
> On all subsequent runs I get this:
>  open("/dev/rtc", O_RDONLY)              = 3
>  ioctl(3, PHN_SET_REGS or RTC_UIE_ON, 0) = -1 EINVAL (Invalid argument)
>  ioctl(3, RTC_RD_TIME, 0x7ffd76b3ae70)   = -1 EINVAL (Invalid argument)
>  close(3)                                = 0"
>
> This was caused by a stupid typo in a patch that should have been
> a simple rename to move around contents of a header file, but
> accidentally wrote zeroes into the rtc rather than reading from
> it.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Fixes: 463a86304cae ("char/genrtc: x86: remove remnants of asm/rtc.h")
> ---
>  arch/x86/kernel/hpet.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
I started seeing system reboots and lockups during kernel boot on a 
prototype HW this week using v4.8-rc1 and bisected to this same commit.

This patch fixes the issue.

Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>