Re: i2c-designware: NULL ptr at RIP: 0010:regmap_read+0x12/0x70

[Jarkko Nikula]

Hi

On 1/11/24 00:56, Kim Phillips wrote:
> Hi,
>
> On 1/9/24 4:11 AM, Jarkko Nikula wrote> On 1/9/24 09:56, V, Narasimhan 
> wrote:
> > >   * Looks like the issue is with this below commit:
> > >   * i2c: designware: Fix lock probe call order in dw_i2c_plat_probe()
> > Hmm... This makes me even more confused since your device AMDI0010 
> > should not even use the access semaphore.
> >
> > So linux-next works if you run a commit before it or revert these 
> > three patches? (commit 2f571a725434 ("i2c: designware: Fix lock probe 
> > call order in dw_i2c_plat_probe()") doesn't revert without reverting 
> > two other related commits after it)
> >
> > git show f9b51f600217b38f46ea39d6aa445e594bf3eb30 |patch -p1 -R
> > git show b8034c7d28a988be82efbf4d65faa847334811f7 |patch -p1 -R
> > git show 2f571a72543463ef07dc3ac61e7b703b9ad997f9 |patch -p1 -R
>
> Narasimhan is right, if I check out, build and boot this commit:
>
>        2f571a725434 i2c: designware: Fix lock probe call order in 
> dw_i2c_plat_probe()
>
> I get the same stacktrace on the serial console.
>
> If I try the previous commit (174a0c565cea "efi/loongarch: Directly 
> position the loaded image file"),
> the system boots fine.
>
> The same thing happens with the three reversions above:
> next-20240110 gets the stacktrace, but with the three
> reversions, it doesn't.
Thanks, I just sent a fix reverting those commits.

> Is your parallel post probe runtime suspending time window
> theory no longer applicable?  These AMD EPYC systems have a
> lot more cores than their client equivalents, and AMD power
> management code has had a lot of improvements lately.
It still a mystery to me but I let Andy to figure out it if he wants to 
during next development cycle :-)