Re: WAS: linux-rt fails to boot on > 3.12.5.-rt7 ... NOW IS: linux-rt-3.14 boots by reverting patches + nvidia uses __rt_mutex_init [which in 3.14 has been changed to EXPORT_SYMBOL_GPL]

[Kimmo Taskinen <kimmo.taskinen@me.com>]

On 14.05.2014 16:18, jordan wrote:
> Hey Kimmo,
>
>>> you can get the patch here; http://pastebin.com/VG7X5WjK ... it
>>> applies over 3.14.3-rt5 [after you've already applied the -rt patch,
>>> you apply it]. It's yielded working AMD Phenom systems for me
>>> [although, i don't have the exact same H/W as you]. it might be worth
>>> a try, just to see if it works.
>> I can confirm that applying the patch in http://pastebin.com/VG7X5WjK to
>> 3.14.3-rt5 makes my system bootable even with AMD C1E enabled.
>> To clarify my previous email, those other tricks "processor.max_cstate=0",
>> "processor.nocst", etc... did not help.
> Well, it looks like you are another person who's system is unstable
> when those 3 upstream -rt patches are applied. Reverting [as you have
> done now] should result in a usable/stable system for you [its worked
> for myself and others for a few releases now. Maybe you can post back
> on how that goes for you?]. Although, depending on config; ie: if you
> are using no_hz_idle/full you may see "NOHZ: softirq pending 40"
> [which one of the patches we reverted fixes, IIRC]. Myself, I don't
> use NO_HZ_* and use the 'periodic timers' in the kernel, instead.
I use also the "periodic timers". There are quite many more who have the 
system effected by this problem. It's the feedback from Daphile users. 
Daphile is my "distro" using the RT kernel (www.daphile.com).

Actually I'm not able give you feedback on the longterm stability of the 
reverted version because the Phenom PC is my home server and I can use 
it only for quick testing. I'm hoping too that Paul or someone else 
finds a better solutions for this :-).

Kimmo
>
> anyway, I am not sure how to fix this, beyond reverting / using that
> patch. I know that some of the devs have had a hard time reproducing
> the problem - maybe Paul will have better luck on another AMD system
> [here is hoping]. But at least for now, you should be able to use that
> patch.
>
> jordan
>
>> Kimmo
>>>
>>>> OK, so I never got back to finding a system that could reproduce this,
>>>> but it sounds like it is still worthwhile; thanks for the reminder and
>>>> I'll go see if I can reproduce this on a quad since the six core was OK.
>>> Hey Paul, I also forgot to get back to you ;) ... I had been carrying
>>> over my .config - so i tried using defconfig too [just to see] and it
>>> was no different. I was astonished that yours booted up just fine,
>>> because i know of other AMD users [aside from Kimmo] who can't boot on
>>> vainlla-rt... Again, 3.14.x-rtX boot and work just fine for me, by
>>> reverting those patches. I had thought maybe -rt5 would boot [it
>>> looked to have some substantial changes], but alas -rt5 also required
>>> the patch for a working system.
>>>
>>> Jordan
>>>
>>>> P.
>>>> --
>>>>
>>>>> Cheers
>>>>> Kimmo
>>>>>
>>>>>> --
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