notebook freezes

[Nate Lawson]

Bruce Evans wrote:
> [Trying to redirect this from current to acpi.]
> 
> On Sun, 4 Mar 2007, Stefan Ehmann wrote:
> 
>> On Sunday 04 March 2007 13:27, Bruce Evans wrote:
>>> On Fri, 2 Mar 2007, Stefan Ehmann wrote:
>>>> On Thursday 01 March 2007 16:12, Stefan Ehmann wrote:
>>>>> My few days old -current freezes if I press Fn-F6 (this is the
>>>>> combination to adjust display brightness) if I've done a
>>>>> suspend/resume
>>>>> before. Directly after boot it works fine.
>>>>
>>>> ...
>>>> So I did a binary search.
>>>>
>>>> src/sys/i386/isa/clock.c r1.231 causes my notebook to freeze.
>>>>
>>>> Reverting this change in a CURRENT from today fixes the problem.
>>>>
>>>> The notebook is still pingable in this state. I experienced some other
>>>> random hangs recently but don't know yet if those are related.
>>>
>>> Oops.  If suspend/resume clobbers the RTC state (which we already
>>> have code
>>> to restore), then it can clobber the RTC index (which even the restoral
>>> code assumes is unclobbered).  Try this fix.
>>>
>>> %%%
>>> Index: clock.c
>>> ===================================================================
>>> RCS file: /home/ncvs/src/sys/i386/isa/clock.c,v
>>> retrieving revision 1.234
>>> diff -u -2 -r1.234 clock.c
>>> --- clock.c    4 Mar 2007 04:55:19 -0000    1.234
>>> +++ clock.c    4 Mar 2007 11:58:00 -0000
>>> @@ -580,4 +582,5 @@
>>>       /* Restore all of the RTC's "status" (actually, control)
>>> registers. */
>>>       /* XXX locking is needed for RTC access. */
>>> +    rtc_reg = -1;
>>>       writertc(RTC_STATUSB, RTCSB_24HR);
>>>       writertc(RTC_STATUSA, rtc_statusa);
>>> %%%
>>>
>>> A similar fix might be needed for amd64, but amd64 doesn't have a resume
>>> hook for putting it in.  The RTC index might get clobbered even if the
>>> data registers aren't.
>>>
>>> I don't know how any of this works with ACPI.  AFAIK (not far), the
>>> resume
>>> hook is only called for APM.
>>
>> Yes, rtc_restore() doesn't get called. So the patch changes nothing
>> for me.

Bruce's patch should work if you add "device pmtimer" to your kernel
config.  That will allow pmtimer_resume() to call timer_restore() which
calls rtc_restore().

If that works for you, Bruce can commit it modulo style bugs.  ;-)

-- 
Nate