Re: Mysterious RTC hangs on x86_64 - fixed, sort of

[Chuck Ebbert <cebbert@redhat.com>]

Zachary Amsden wrote:
> With this patch, /sbin/hwclock no longer hangs my AMD64 machine when run
> after reaching multiuser.  What I don't understand is why.  I have the
> RTC based sound sequencer timer as a module, but not loaded, and the
> error message I added to indicate broken rtc control does not fire.
> 
> So why is it that if I stop taking the rtc_task_lock and issuing the
> callbacks which should never be held or exist that my system no longer
> hard freezes?
> 
> --- /tmp/a      2007-05-03 15:36:07.451256181 -0700
> +++ drivers/char/rtc.c  2007-05-03 15:27:49.000000000 -0700
> @@ -265,10 +265,10 @@
>         spin_unlock (&rtc_lock);
>  
>         /* Now do the rest of the actions */
> -       spin_lock(&rtc_task_lock);
> -       if (rtc_callback)
> -               rtc_callback->func(rtc_callback->private_data);
> -       spin_unlock(&rtc_task_lock);
> +/*     spin_lock(&rtc_task_lock); */
> +//     if (rtc_callback)
> +//             rtc_callback->func(rtc_callback->private_data);
> +/*     spin_unlock(&rtc_task_lock); */
>         wake_up_interruptible(&rtc_wait);       

Try leaving the spinlocks and just disabling the callbacks. And maybe
enable spinlock debugging...

> 
> CONFIG_HPET_EMULATE_RTC=y

Did you try without that?