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Old 01-31-2009, 09:43 PM
Dale
 
Default /dev/rtc => rtc0

Mark Knecht wrote:
> Hi,
> I know nothing of this part of the Linux boot process. If it's
> *fairly* simple can someone point me at the right stuff to understand
> how Gentoo creates a link from /dev/rtc to rtc0? When in the boot
> process does this link become valid?
>
> Is it something that's held in a file and recreated from that file
> on each boot? Is it created automagically by Gentoo Angels that look
> after my well being but seldom reveal themselves? Is it created by the
> kernel itself when something is specifically configured to do so?
> Something else?
>
> Thanks,
> Mark
>
> lightning src # uname -a
> Linux lightning 2.6.27-gentoo-r8 #6 Fri Jan 30 18:55:56 PST 2009
> x86_64 AMD Athlon(tm) 64 Processor 3000+ AuthenticAMD GNU/Linux
> lightning src # ls -al /dev/rtc*
> lrwxrwxrwx 1 root root 4 2009-01-30 10:58 /dev/rtc -> rtc0
> crw-r--r-- 1 root root 254, 0 2009-01-30 10:58 /dev/rtc0
> lightning src #
>
>
>

From my understanding udev creates all the "stuff" in /dev. You can
change the rules that it uses to make them tho. I think there is
documentation on gentoo.org to help with that. So far, mine has worked
well enough. Lucky I guess.

That help?

Dale

:-) :-)
 
Old 01-31-2009, 09:56 PM
Mark Knecht
 
Default /dev/rtc => rtc0

On Sat, Jan 31, 2009 at 2:43 PM, Dale <rdalek1967@gmail.com> wrote:
> Mark Knecht wrote:
>> Hi,
>> I know nothing of this part of the Linux boot process. If it's
>> *fairly* simple can someone point me at the right stuff to understand
>> how Gentoo creates a link from /dev/rtc to rtc0? When in the boot
>> process does this link become valid?
>>
>> Is it something that's held in a file and recreated from that file
>> on each boot? Is it created automagically by Gentoo Angels that look
>> after my well being but seldom reveal themselves? Is it created by the
>> kernel itself when something is specifically configured to do so?
>> Something else?
>>
>> Thanks,
>> Mark
>>
>> lightning src # uname -a
>> Linux lightning 2.6.27-gentoo-r8 #6 Fri Jan 30 18:55:56 PST 2009
>> x86_64 AMD Athlon(tm) 64 Processor 3000+ AuthenticAMD GNU/Linux
>> lightning src # ls -al /dev/rtc*
>> lrwxrwxrwx 1 root root 4 2009-01-30 10:58 /dev/rtc -> rtc0
>> crw-r--r-- 1 root root 254, 0 2009-01-30 10:58 /dev/rtc0
>> lightning src #
>>
>>
>>
>
> From my understanding udev creates all the "stuff" in /dev. You can
> change the rules that it uses to make them tho. I think there is
> documentation on gentoo.org to help with that. So far, mine has worked
> well enough. Lucky I guess.
>
> That help?
>
> Dale

Hi Dale,
While poking around in a bunch of different kernel config files -
some gentoo-sources - some not - I found there is an option in

Device Drivers -> RTC

that ONLY shows up when you tell the kernel to build the support in.
(I.e. - not off or modular) The option says

<*> Set system time from RTC on startup or resume
(rtc0) RTC used to set the system time

So, it appears it's a kernel oriented thing which allows it to get set
very early in the boot process. My problem on a kernel I built
yesterday was "File has a date in the future" sort of messages. I had
this set as modular so it couldn't load that early. The other problem
was that since it was a module and apparently I didn't load that
module the command hwclock -r failed.

I've reconfigured the kernel and will build it and test after I get
finished with an emerge -e world later today.

Thanks for the response. Hope this info helps someone else in the
future. (and me after the reboot!) ;-)

Cheers,
Mark
 
Old 01-31-2009, 10:17 PM
Dale
 
Default /dev/rtc => rtc0

Mark Knecht wrote:
> On Sat, Jan 31, 2009 at 2:43 PM, Dale <rdalek1967@gmail.com> wrote:
>
>> Mark Knecht wrote:
>>
>>> Hi,
>>> I know nothing of this part of the Linux boot process. If it's
>>> *fairly* simple can someone point me at the right stuff to understand
>>> how Gentoo creates a link from /dev/rtc to rtc0? When in the boot
>>> process does this link become valid?
>>>
>>> Is it something that's held in a file and recreated from that file
>>> on each boot? Is it created automagically by Gentoo Angels that look
>>> after my well being but seldom reveal themselves? Is it created by the
>>> kernel itself when something is specifically configured to do so?
>>> Something else?
>>>
>>> Thanks,
>>> Mark
>>>
>>> lightning src # uname -a
>>> Linux lightning 2.6.27-gentoo-r8 #6 Fri Jan 30 18:55:56 PST 2009
>>> x86_64 AMD Athlon(tm) 64 Processor 3000+ AuthenticAMD GNU/Linux
>>> lightning src # ls -al /dev/rtc*
>>> lrwxrwxrwx 1 root root 4 2009-01-30 10:58 /dev/rtc -> rtc0
>>> crw-r--r-- 1 root root 254, 0 2009-01-30 10:58 /dev/rtc0
>>> lightning src #
>>>
>>>
>>>
>>>
>> From my understanding udev creates all the "stuff" in /dev. You can
>> change the rules that it uses to make them tho. I think there is
>> documentation on gentoo.org to help with that. So far, mine has worked
>> well enough. Lucky I guess.
>>
>> That help?
>>
>> Dale
>>
>
> Hi Dale,
> While poking around in a bunch of different kernel config files -
> some gentoo-sources - some not - I found there is an option in
>
> Device Drivers -> RTC
>
> that ONLY shows up when you tell the kernel to build the support in.
> (I.e. - not off or modular) The option says
>
> <*> Set system time from RTC on startup or resume
> (rtc0) RTC used to set the system time
>
> So, it appears it's a kernel oriented thing which allows it to get set
> very early in the boot process. My problem on a kernel I built
> yesterday was "File has a date in the future" sort of messages. I had
> this set as modular so it couldn't load that early. The other problem
> was that since it was a module and apparently I didn't load that
> module the command hwclock -r failed.
>
> I've reconfigured the kernel and will build it and test after I get
> finished with an emerge -e world later today.
>
> Thanks for the response. Hope this info helps someone else in the
> future. (and me after the reboot!) ;-)
>
> Cheers,
> Mark
>
>
>

My CMOS time chip sucks on this mobo. Everything else rocks but that
stupid clock and yes I have checked the battery. Anyway, I get that
error all the time. If I just reboot it does all right but if I do a
shutdown, that error pops up. Sometimes it may only be a few seconds
off, sometimes several hours to a day. I have never had it hurt
anything here tho. It just warns you I guess.

Dale

:-) :-)
 

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