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Groups > linux.debian.kernel > #64552

Bug#932845: TS-219 RTC issue with Debian Buster

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Hello Uwe,

On 26.07.19 09:27, Uwe Kleine-König wrote:
> Hello Alexandre,
> 
> On Thu, Jul 25, 2019 at 04:31:49PM +0200, Oliver Hartkopp wrote:
>> On 24.07.19 09:07, Uwe Kleine-König wrote:
>>> On Tue, Jul 23, 2019 at 10:28:18PM +0200, Oliver Hartkopp wrote:
>>>> I'm running a TS-119P+ and a TS-219P II Qnap NAS with Debian Buster.
>>>> Both are now running a linux-image-4.19.0-5-marvell kernel.
>>>>
>>>> But since my update from Linux 4.9 (Stretch) to Linux 4.19 (Buster) the
>>>> hardware clock of both boxes refuse to work.
>>>>
>>>> After some digging in kernel sources and re-installing Linux 4.9 on my
>>>> Buster setup it turns out, that a change in the kernel config causes the
>>>> problem:
>>>>
>>>> 4.19.0-5-marvell -> CONFIG_RTC_DRV_S35390A=m   (fails)
>>>>
>>>> 4.9.0-4-marvell -> CONFIG_RTC_DRV_S35390A=y    (works)
>>>>
>>>> See details and solving process at:
>>>>
>>>> https://marc.info/?l=linux-arm-kernel&m=156390875629259&w=2
>>>>
>>>> Can you please revert the Kernel config parts for the RTC in a way that the
>>>> RTC drivers are built into the marvell-arch kernel again instead of building
>>>> them as modules?
>>>
>>> They were switched to modules because the kernel image got too big to
>>> fit into the flash storage of some machines. I assume when we switch to
>>> built-in again the resulting problem is the bigger one.
>>
>> I don't know which is the bigger problem here.
>>
>> When the rtc driver is built as module it can not be operated with the
>> hwclock tool from the util-linux package due to the missing rtc UIE support.
>>
>> You finally have no hardware clock on these machines and must wait for ntp
>> to shift time and date (my system always starts in February until ntp fixes
>> the time).
> 
> For me it's obvious what is the bigger problem. Either you don't have
> the correct time until ntp fixes it up for you, or others cannot install
> a kernel update and so run a vulnerable OS.

That what I've written, NTP fixes the time for me. I have no problem 
with updating my kernels - in fact I was even able to flash an older 
kernel to figure out this rtc issue :-)

>> Maybe this problem is only relevant for the S35390A and PCF8563 chip which
>> both lack the UIE support needed by hwclock. Both have only alarm triggers
>> in a minute accuracy according to the driver source code.
> 
> AFAIK the rtc framework should then emulate this event somehow.

I don't think so. When the rtc chip is not able to trigger an event with 
a one second resolution - how can you emulate that?

>> So CONFIG_RTC_DRV_S35390A=y and CONFIG_RTC_DRV_PCF8563=y should bring back
>> the hw clocks on these machines.
>>
>> I assume using hwclock without UIE trigger code will impact the accuracy.
>>
>>>> As described in the referenced description the hwclock tool does not work on
>>>> the machines.
>>>
>>> I'm not sure yet if this is a problem in hwclock() or the s35390a
>>> driver.
>>
>> In detail it is hwclock together with rtc drivers not supporting UIE trigger
>> with a 1 second resolution.
> 
> @abelloni: Do you can shed some light here, how it is supposed to work?
> Is hwclock just doing it wrong with non-PC clocks, or is there a kernel
> bug to fix?
> 
> Best regards
> Uwe
> 

Best regards,
Oliver

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Thread

Bug#932845: TS-219 RTC issue with Debian Buster Oliver Hartkopp <socketcan@hartkopp.net> - 2019-07-23 22:40 +0200
  Bug#932845: TS-219 RTC issue with Debian Buster Uwe Kleine-König <uwe@kleine-koenig.org> - 2019-07-24 09:20 +0200
    Bug#932845: TS-219 RTC issue with Debian Buster Oliver Hartkopp <socketcan@hartkopp.net> - 2019-07-25 16:50 +0200
      Bug#932845: TS-219 RTC issue with Debian Buster Uwe Kleine-König <u.kleine-koenig@pengutronix.de> - 2019-07-26 09:50 +0200
        Bug#932845: TS-219 RTC issue with Debian Buster Oliver Hartkopp <socketcan@hartkopp.net> - 2019-07-26 11:40 +0200
          Bug#932845: TS-219 RTC issue with Debian Buster Alexandre Belloni <alexandre.belloni@bootlin.com> - 2019-07-26 11:50 +0200
            Bug#932845: TS-219 RTC issue with Debian Buster Oliver Hartkopp <socketcan@hartkopp.net> - 2019-07-26 12:40 +0200
              Bug#932845: TS-219 RTC issue with Debian Buster Oliver Hartkopp <socketcan@hartkopp.net> - 2019-07-26 13:00 +0200
  Bug#932845: TS-219 RTC issue with Debian Buster Oliver Hartkopp <socketcan@hartkopp.net> - 2019-07-26 21:20 +0200
  Bug#932845: TS-219 RTC issue with Debian Buster Uwe Kleine-König <u.kleine-koenig@pengutronix.de> - 2019-07-28 21:50 +0200
    Bug#932845: TS-219 RTC issue with Debian Buster Oliver Hartkopp <socketcan@hartkopp.net> - 2019-07-29 08:30 +0200
  Processed: Re: Bug#932845: TS-219 RTC issue with Debian Buster "Debian Bug Tracking System" <owner@bugs.debian.org> - 2019-07-28 21:50 +0200

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