X86: Impossible select Enhanced Real Time Clock Support (legacy PC RTC driver)

X86: Impossible select Enhanced Real Time Clock Support (legacy PC RTC driver)

[Stefani Seibold]

Since some kernel version it is impossible to select the Enhanced Real
Time Clock Support (legacy PC RTC driver) because RTC_LIB is set by
default in arch/x86/Kconfig, but the rule for selecting CONFIG_RTC is
RTC_LIB=n. So the code of driver/char/rtc is still useless.

This breaks the API since there is no more misc device /dev/rtc
available without a udev rule or a link to /dev/rtc0. 

Re: X86: Impossible select Enhanced Real Time Clock Support (legacy PC RTC driver)

[Randy Dunlap]

[adding more patch committers]

On 04/13/2014 12:05 PM, Stefani Seibold wrote:
> Since some kernel version it is impossible to select the Enhanced Real
> Time Clock Support (legacy PC RTC driver) because RTC_LIB is set by
> default in arch/x86/Kconfig, but the rule for selecting CONFIG_RTC is
> RTC_LIB=n. So the code of driver/char/rtc is still useless.
> 
> This breaks the API since there is no more misc device /dev/rtc
> available without a udev rule or a link to /dev/rtc0. 


-- 
~Randy

Re: X86: Impossible select Enhanced Real Time Clock Support (legacy PC RTC driver)

[John Stultz]

On Mon, Apr 21, 2014 at 10:58 AM, Randy Dunlap <rdunlap@infradead.org> wrote:
> [adding more patch committers]
>
> On 04/13/2014 12:05 PM, Stefani Seibold wrote:
>> Since some kernel version it is impossible to select the Enhanced Real
>> Time Clock Support (legacy PC RTC driver) because RTC_LIB is set by
>> default in arch/x86/Kconfig, but the rule for selecting CONFIG_RTC is
>> RTC_LIB=n. So the code of driver/char/rtc is still useless.
>>
>> This breaks the API since there is no more misc device /dev/rtc
>> available without a udev rule or a link to /dev/rtc0.

So yea.. I feel like that /dev/rtcN renaming (and API) break (which
was a huge and annoying pain) was back in the 2.6.18-ish era?

But it sounds like the driver/char/rtc bit is dead code, and needs a
cleanup? Or is there some use of that code that you need that the
generic RTC layer doesn't have?

thanks
-john

Re: X86: Impossible select Enhanced Real Time Clock Support (legacy PC RTC driver)

[Alessandro Zummo]

On Mon, 28 Apr 2014 11:16:37 -0700
John Stultz <john.stultz@linaro.org> wrote:

> >> This breaks the API since there is no more misc device /dev/rtc
> >> available without a udev rule or a link to /dev/rtc0.  
> 
> So yea.. I feel like that /dev/rtcN renaming (and API) break (which
> was a huge and annoying pain) was back in the 2.6.18-ish era?

 It's very old and linking/renaming is around since then.

> But it sounds like the driver/char/rtc bit is dead code, and needs a
> cleanup? Or is there some use of that code that you need that the
> generic RTC layer doesn't have?

 as far as I know, no recent distribution is using the old code
 anymore and the new (well, not so new anymore) framework provides the same functionality.
 

-- 

 Best regards,

 Alessandro Zummo,
  Tower Technologies - Torino, Italy

  http://www.towertech.it

Re: X86: Impossible select Enhanced Real Time Clock Support (legacy PC RTC driver)

[Stefani Seibold]

On Mon, 2014-04-28 at 20:20 +0200, Alessandro Zummo wrote:
> On Mon, 28 Apr 2014 11:16:37 -0700
> John Stultz <john.stultz@linaro.org> wrote:
> 
> > >> This breaks the API since there is no more misc device /dev/rtc
> > >> available without a udev rule or a link to /dev/rtc0.  
> > 
> > So yea.. I feel like that /dev/rtcN renaming (and API) break (which
> > was a huge and annoying pain) was back in the 2.6.18-ish era?
> 
>  It's very old and linking/renaming is around since then.
> 
> > But it sounds like the driver/char/rtc bit is dead code, and needs a
> > cleanup? Or is there some use of that code that you need that the
> > generic RTC layer doesn't have?
> 

The driver/char/rtc is not working code and should be a wrapper to the
first rtc device.

>  as far as I know, no recent distribution is using the old code
>  anymore and the new (well, not so new anymore) framework provides the same functionality.
>  

Embedded distribution use it and depending on the /dev/rtc device. So
what is missing is the /dev/rtc misc device 10,135.

- Stefani

Re: X86: Impossible select Enhanced Real Time Clock Support (legacy PC RTC driver)

[Maciej W. Rozycki]

On Mon, 28 Apr 2014, Alessandro Zummo wrote:

> > But it sounds like the driver/char/rtc bit is dead code, and needs a
> > cleanup? Or is there some use of that code that you need that the
> > generic RTC layer doesn't have?
> 
>  as far as I know, no recent distribution is using the old code anymore 
>  and the new (well, not so new anymore) framework provides the same 
>  functionality.

 Well, the handling of update-ended interrupts is still missing, as is 
some non-x86 stuff I posted a fix for recently (still pending review, can 
you please look into it sometime?).

  Maciej

Re: [rtc-linux] Re: X86: Impossible select Enhanced Real Time Clock Support (legacy PC RTC driver)

[Alessandro Zummo]

On Tue, 6 May 2014 00:34:41 +0100 (BST)
"Maciej W. Rozycki" <macro@linux-mips.org> wrote:

>  Well, the handling of update-ended interrupts is still missing, as is 
> some non-x86 stuff I posted a fix for recently (still pending review, can 
> you please look into it sometime?).

 Done, sorry for the delay. 

-- 

 Best regards,

 Alessandro Zummo,
  Tower Technologies - Torino, Italy

  http://www.towertech.it