Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>> Gilles Chanteperdrix wrote:
>>> Jan Kiszka wrote:
>>>> Gilles Chanteperdrix wrote:
>>>>> Daniele Nicolodi wrote:
>>>>>> Booting a working 2.6.30 kernel I noticed this error message as first
>>>>>> output on the console. Can it be related to my issue with more modern
>>>>>> kernels and ipipe patches?
>>>>>>
>>>>>> ERROR: 8254 timer not connected to IO-APIC
>>>>>>
>>>>>> I have no idea of what it means.
>>>>> Is APIC enabled in your kernel configuration?
>>>> It likely is.
>>>>
>>>> I'm getting this error for many kernel releases now. It must be related
>>>> to I-pipe's patching of the APIC or IO-APIC code. Irritating but mostly
>>>> harmless.
>>> What I mean is that when Xenomai wants to use the 8254 (which is the
>>> case if the APIC is disabled in linux kernel configuration) and the 8254
>>> has become unreachable by Linux by some change in recent versions,
>>> Xenomai timing subystem becomes screwed up.
>>>
>>> When, on the other hand, Xenomai wants to use the APIC, the fact that
>>> the 8254 has become unreachable is harmless.
>> ...but people continue to report this as bug.
> 
> But I am not sure this bug is related to Xenomai at all.

At least it goes away when disabling CONFIG_IPIPE.

It's harmless, it's just that the kernels cries a bit too loud.

Jan