From: Len Brown <lenb@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: "Serge Belyshev" <belyshev@depni.sinp.msu.ru>,
"Dirk Gouders" <dirk@gouders.net>,
"Mickaël Salaün" <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
Date: Mon, 1 Feb 2021 23:22:50 -0500 [thread overview]
Message-ID: <CAJvTdK=S+FTMUWyFgHMcZ2xKJKDrjE_9a-cb5hHcBT4MvoyJxg@mail.gmail.com> (raw)
In-Reply-To: <87zh0nbnha.fsf@nanos.tec.linutronix.de>
Thanks for the update, Thomas.
V1 prevented rc6 automated suspend/resume testing on all 13 of my
local machines.
V2 applied, and they are back in business.
tested-by: Len Brown <len.brown@intel.com>
On Mon, Feb 1, 2021 at 2:25 PM Thomas Gleixner <tglx@linutronix.de> 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(-)
>
> --- a/drivers/rtc/rtc-cmos.c
> +++ b/drivers/rtc/rtc-cmos.c
> @@ -805,8 +805,8 @@ cmos_do_probe(struct device *dev, struct
>
> spin_lock_irq(&rtc_lock);
>
> - /* Ensure that the RTC is accessible. Bit 0-6 must be 0! */
> - if ((CMOS_READ(RTC_VALID) & 0x7f) != 0) {
> + /* Ensure that the RTC is accessible. Bit 6 must be 0! */
> + if ((CMOS_READ(RTC_VALID) & 0x40) != 0) {
> spin_unlock_irq(&rtc_lock);
> dev_warn(dev, "not accessible\n");
> retval = -ENXIO;
> --- a/drivers/rtc/rtc-mc146818-lib.c
> +++ b/drivers/rtc/rtc-mc146818-lib.c
> @@ -21,8 +21,8 @@ unsigned int mc146818_get_time(struct rt
>
> again:
> spin_lock_irqsave(&rtc_lock, flags);
> - /* Ensure that the RTC is accessible. Bit 0-6 must be 0! */
> - if (WARN_ON_ONCE((CMOS_READ(RTC_VALID) & 0x7f) != 0)) {
> + /* Ensure that the RTC is accessible. Bit 6 must be 0! */
> + if (WARN_ON_ONCE((CMOS_READ(RTC_VALID) & 0x40) != 0)) {
> spin_unlock_irqrestore(&rtc_lock, flags);
> memset(time, 0xff, sizeof(*time));
> return 0;
--
Len Brown, Intel Open Source Technology Center
next prev parent reply other threads:[~2021-02-02 4:23 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-06 21:46 [patch 0/8] ntp/rtc: Fixes and cleanups Thomas Gleixner
2020-12-06 21:46 ` [patch 1/8] rtc: mc146818: Prevent reading garbage Thomas Gleixner
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2021-01-25 18:40 ` [patch 1/8] rtc: mc146818: Prevent reading garbage - bug Mickaël Salaün
2021-01-26 13:26 ` Thomas Gleixner
2021-01-26 14:17 ` Mickaël Salaün
2021-01-26 15:35 ` Thomas Gleixner
2021-01-26 17:02 ` [PATCH V2] rtc: mc146818: Detect and handle broken RTCs Thomas Gleixner
2021-01-26 18:00 ` Alexandre Belloni
2021-01-27 8:41 ` [tip: timers/urgent] " tip-bot2 for Thomas Gleixner
[not found] ` <ghft2hwevu.fsf@gouders.net>
2021-02-01 13:53 ` [PATCH V2] " Serge Belyshev
2021-02-01 19:09 ` [PATCH] rtc: mc146818: Dont test for bit 0-5 in Register D Thomas Gleixner
2021-02-01 19:24 ` [PATCH V2] " Thomas Gleixner
2021-02-01 19:32 ` Linus Torvalds
2021-02-01 19:40 ` Thomas Gleixner
2021-02-11 23:09 ` Maciej W. Rozycki
2021-02-01 19:38 ` Alexandre Belloni
2021-02-01 20:09 ` Borislav Petkov
2021-02-01 20:15 ` Dirk Gouders
2021-02-02 4:22 ` Len Brown [this message]
2021-02-02 19:40 ` [tip: timers/urgent] " tip-bot2 for Thomas Gleixner
2021-02-03 13:00 ` [PATCH V2] " Mickaël Salaün
2020-12-06 21:46 ` [patch 2/8] rtc: mc146818: Reduce spinlock section in mc146818_set_time() Thomas Gleixner
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-06 21:46 ` [patch 3/8] rtc: cmos: Make rtc_cmos sync offset correct Thomas Gleixner
2020-12-07 20:50 ` Jason Gunthorpe
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-06 21:46 ` [patch 4/8] rtc: core: Make the sync offset default more realistic Thomas Gleixner
2020-12-07 20:55 ` Jason Gunthorpe
2020-12-10 23:59 ` Alexandre Belloni
2020-12-11 0:23 ` Thomas Gleixner
2020-12-11 0:28 ` Alexandre Belloni
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-06 21:46 ` [patch 5/8] ntp: Make the RTC synchronization more reliable Thomas Gleixner
2020-12-07 12:47 ` Miroslav Lichvar
2020-12-07 20:59 ` Jason Gunthorpe
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-29 19:41 ` [patch 5/8] " Geert Uytterhoeven
2021-01-11 10:12 ` Thomas Gleixner
2021-01-11 10:40 ` Geert Uytterhoeven
2020-12-06 21:46 ` [patch 6/8] ntp, rtc: Move rtc_set_ntp_time() to ntp code Thomas Gleixner
2020-12-07 20:59 ` Jason Gunthorpe
2020-12-09 3:51 ` Alexandre Belloni
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-06 21:46 ` [patch 7/8] ntp: Make the RTC sync offset less obscure Thomas Gleixner
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-06 21:46 ` [patch 8/8] ntp: Consolidate the RTC update implementation Thomas Gleixner
2020-12-07 21:05 ` Jason Gunthorpe
2020-12-11 9:23 ` Thomas Gleixner
2020-12-11 10:07 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-09 0:33 ` [patch 0/8] ntp/rtc: Fixes and cleanups Thomas Gleixner
2020-12-09 4:01 ` Alexandre Belloni
2020-12-09 12:39 ` Thomas Gleixner
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