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Date:   Mon, 1 Feb 2021 21:09:25 +0100
From:   Borislav Petkov <bp@alien8.de>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     Serge Belyshev <belyshev@depni.sinp.msu.ru>,
        Dirk Gouders <dirk@gouders.net>,
        =?utf-8?Q?Micka=C3=ABl_Sala=C3=BCn?= <mic@digikod.net>,
        LKML <linux-kernel@vger.kernel.org>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Miroslav Lichvar <mlichvar@redhat.com>,
        John Stultz <john.stultz@linaro.org>,
        Prarit Bhargava <prarit@redhat.com>,
        Alessandro Zummo <a.zummo@towertech.it>,
        linux-rtc@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH V2] rtc: mc146818: Dont test for bit 0-5 in Register D
Message-ID: <20210201200925.GA20521@zn.tnic>
References: <20201206220541.594826678@linutronix.de>
 <19a7753c-c492-42e4-241a-8a052b32bb63@digikod.net>
 <871re7hlsg.fsf@nanos.tec.linutronix.de>
 <98cb59e8-ecb4-e29d-0b8f-73683ef2bee7@digikod.net>
 <87y2gfg18p.fsf@nanos.tec.linutronix.de>
 <87tur3fx7w.fsf@nanos.tec.linutronix.de>
 <ghft2hwevu.fsf@gouders.net>
 <877dnrc2sv.fsf@depni.sinp.msu.ru>
 <8735yfd2q4.fsf@nanos.tec.linutronix.de>
 <87zh0nbnha.fsf@nanos.tec.linutronix.de>
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On Mon, Feb 01, 2021 at 08:24:17PM +0100, Thomas Gleixner wrote:
> The recent change to validate the RTC turned out to be overly tight.
> 
> While it cures the problem on the reporters machine it breaks machines
> with Intel chipsets which use bit 0-5 of the D register. So check only
> for bit 6 being 0 which is the case on these Intel machines as well.
> 
> Fixes: 211e5db19d15 ("rtc: mc146818: Detect and handle broken RTCs")
> Reported-by: Serge Belyshev <belyshev@depni.sinp.msu.ru>
> Reported-by: Dirk Gouders <dirk@gouders.net>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> V2: Provide the actual delta patch. Should have stayed away from
>     computers today....
> ---
>  drivers/rtc/rtc-cmos.c         |    4 ++--
>  drivers/rtc/rtc-mc146818-lib.c |    4 ++--
>  2 files changed, 4 insertions(+), 4 deletions(-)

FWIW:

Reported-by: Borislav Petkov <bp@suse.de>
Tested-by: Borislav Petkov <bp@suse.de>

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette