Re: 2.6.26.8-rt12 - No hwclock - works under 2.6.24-rt1

[Clark Williams <williams@redhat.com>]

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On Fri, 30 Jan 2009 16:00:27 -0800
Mark Knecht <markknecht@gmail.com> wrote:

> I'm just getting around to trying 2.6.26.8-rt12 from the Gentoo
> pro-audio overlay. I built the kernel using an older .config and make
> oldconfig so maybe it didn't catch something correctly. Anyway, at
> boot the system is complaining about all file times are in the future
> and later on I see a message that it couldn't set the clock and I'll
> have to do that by hand. The machine then finishes booting and I get
> as far as X. Haven't tested anything more than that.
> 
> the issue seems to be that the system cannot find my hardware clock,
> and frankly neither can I in make menuconfig so maybe someone can tell
> me where is the hardware clock? I'm hoping it's just misconfiguration
> and not something more devious.
> 
> Motherboard is an Asus A8N-E which is nVidia based. More info provided
> if need be.
> 
> Thanks,
> Mark
> 
> [NEW KERNEL]
> 
> lightning ~ # uname -a
> Linux lightning 2.6.26.8-rt12 #1 PREEMPT RT Fri Jan 30 12:39:38 PST
> 2009 x86_64 AMD Athlon(tm) 64 Processor 3000+ AuthenticAMD GNU/Linux
> lightning ~ # hwclock -r
> Cannot access the Hardware Clock via any known method.
> Use the --debug option to see the details of our search for an access method.
> lightning ~ #

As I recall this was a change in the rtc driver where it uses classes
(and you can have multiple rtc device instances).  The result is that
the rtc driver no longer creates /dev/rtc but rather /dev/rtc0. 

You might try just creating a symlink in /dev from rtc -> rtc0 and see
if that makes your startup logic happy. I don't think that using udev
to create your symlink on the fly is an option, because most distros
access the RTC before udev gets run.

You might also make sure that CONFIG_RTC_DRV_CMOS=y, so that you don't
have to load a module from an initrd to get to the cmos clock.

Clark

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