[FSL P50x0] Xorg always restarts again and again after the the PowerPC updates 5.13-1

[Christian Zigotzky]

On 13 May 2021 at 07:00pm, Christophe Leroy wrote:
>
>
> Le 13/05/2021 à 18:35, Christian Zigotzky a écrit :
>> On 13 May 2021 at 5:51pm, Christophe Leroy wrote:
>>>
>>>
>>> Le 13/05/2021 à 17:19, Christian Zigotzky a écrit :
>>>> On 13 May 2021 at 12:01 pm, Christophe Leroy wrote:
>>>>>
>>>>>
>>>>> Le 13/05/2021 à 08:47, Christian Zigotzky a écrit :
>>>>>> Hi Christophe,
>>>>>>
>>>>>>> On 9. May 2021, at 19:37, Christophe Leroy 
>>>>>>> <christophe.leroy at csgroup.eu> wrote:
>>>>>>>
>>>>>>> Did I do an error in my analysis ?
>>>>>>
>>>>>> No, you didn’t. On the contrary you have found the issue. ;-) The 
>>>>>> issue is somewhere in the new interrupt code.
>>>>>
>>>>> I'm not convinced, but let's give it a try.
>>>>>
>>>>>>
>>>>>>> ZZ | * | ceff77efa4f8 powerpc/64e/interrupt: Use new interrupt 
>>>>>>> context tracking scheme
>>>>>>
>>>>>> Could you please create a patch for reverting the new interrupt 
>>>>>> code? I would like to confirm your result.
>>>>>
>>>>> Please fetch https://github.com/chleroy/linux.git and try the 
>>>>> branch for_christian.
>>>>>
>>>>> This is a revert of approx a dozen of commits around the changes 
>>>>> to 64e on top of v5.13-rc1.
>>>>>
>>>>> If the top of the branch works for you, it would be great if you 
>>>>> can find out which one of the reverts fixes the problem for real.
>>>>>
>>>>> Thanks
>>>>> Christophe
>>>> It's working! Great! I can use the RC1 on my FSL P5040. Thank you! 
>>>> The issue is definitely somewhere in the interrupt code. Please 
>>>> tell me the next steps.
>>>>
>>>
>>> Can you bisect between 5.13-rc1 and the top of the 'for_christian' 
>>> branch to find the first 'good' commit ?
>>>
>>> Take care it is an "up side down" bisect, a 'good' is one that does 
>>> _not_ work and a 'bad' is a commit that works.
>>>
>>> git bisect start
>>> git bisect bad 1c8f441f1485
>>> git bisect good 6efb943b8616
>>>
>>> Christophe
>> Hi Christophe,
>>
>> Yes, I can. Shall I use the branch 'for_christian' or the default 
>> linux git for bisecting? I have tried it already with the branch 
>> 'for_christian' but it doesn't compile.
>>
>> git bisect start
>> git bisect bad 1c8f441f1485
>> git bisect good 6efb943b8616
>>
>> Output: [d66b1d1aab0c1caad11eca417f515b86ec0bebe9] Revert 
>> "powerpc/64e/interrupt: Use new interrupt context tracking scheme"
>>
>> Result:
>>
>> arch/powerpc/kernel/interrupt.o: In function `.syscall_exit_prepare':
>> interrupt.c:(.text+0x278): undefined reference to `.schedule_user'
>> arch/powerpc/kernel/interrupt.o: In function 
>> `.interrupt_exit_user_prepare':
>> interrupt.c:(.text+0x340): undefined reference to `.schedule_user'
>> Makefile:1191: recipe for target 'vmlinux' failed
>> make: *** [vmlinux] Error 1
>>
>
> Ah yes, I remember this problem.
>
> Can you select CONFIG_VIRT_CPU_ACCOUNTING_GEN in your configuration ?
>
> Otherwise, I can try to fix the branch.
>
> Christophe
I selected this. After that it compiles.

1. git bisect good - Xorg restarts again and again
     Output: [f9aa0ac1e9e82b60401ad567bdabc30598325bc1] Revert 
"powerpc/64e/interrupt: use new interrupt return"
2. git bisect good - Xorg restarts again and again
     Output: [cd6d259a14704741bf0cd1dcadb84c0de22d7f77] Revert 
"powerpc/64e/interrupt: always save nvgprs on interrupt"
3. git bisect bad - Xorg works
     Output: [9bfa20ef2ae54d3b9088dfbcde4ef97062cf5ef2] Revert 
"powerpc/interrupt: update common interrupt code for"
4. git bisect good - Xorg restarts again and again
     Output:

cd6d259a14704741bf0cd1dcadb84c0de22d7f77 is the first bad commit
commit cd6d259a14704741bf0cd1dcadb84c0de22d7f77
Author: Christophe Leroy <christophe.leroy at csgroup.eu>
Date:   Thu May 13 09:52:06 2021 +0000

     Revert "powerpc/64e/interrupt: always save nvgprs on interrupt"

     This reverts commit 4228b2c3d20e9f80b847f809c38e6cf82864fa50.

:040000 040000 156542c857ad72776b69bb67b2f244afeeb7abd3 
92ea86ed097fce16238b0c2f2b343473894e4e8e M    arch

- Christian