Fwd: BUG: Patch to spi-nor hangs Lenovo ThinkPad X1 Titanium with divide by zero

[Bagas Sanjaya <bagasdotme@gmail.com>]

Hi,

I notice a regression report on Bugzilla [1]. Quoting from it:

> This is the system I'm having troubles with:
> 
> os-version              : Ubuntu 20.04.2 LTS
> baseboard-manufacturer  : LENOVO
> baseboard-product-name  : 20QA000FUS
> baseboard-serial-number : W1KS11R111D
> baseboard-version       : SDK0J40697 WIN
> bios-release-date       : 05/20/2021
> bios-vendor             : LENOVO
> bios-version            : N2MET49W (1.14 )
> chassis-manufacturer    : LENOVO
> chassis-serial-number   : R911Q4MM
> chassis-version         : None
> processor-manufacturer  : Intel(R) Corporation
> processor-version       : 11th Gen Intel(R) Core(TM) i7-1160G7 @ 1.20GHz
> system-manufacturer     : LENOVO
> system-product-name     : 20QA000FUS
> system-serial-number    : R911Q4MM
> system-version          : ThinkPad X1 Titanium Gen 1
> cpucount                : 8
> memtotal                : 15939728 kB
> memfree                 : 8428028 kB
> 
> Ever since 6.4-rc1 this system has hung on every S3/S2idle suspend and shutdown during reboot. I've bisected it to a patch to the MTD: SPI-NOR subsystem about introducing the "concept of a bank"
> Basically something about the new code is improperly handling the memory size on this machine. It's not complex but I haven't dug any deeper since I want it posted as quickly as possible. To reproduce, run any of these 3 commands and the system will hang:
> 
> echo freeze > /sys/power/state
> echo mem > /sys/power/state
> sudo reboot
> 

For the full thread, see bugzilla.

Fortunately, the reporter also sent out potential fix for this regression;
but to be sure it doesn't fall through cracks, I'm adding it to regzbot:

#regzbot introduced: 9d6c5d64f0288a https://bugzilla.kernel.org/show_bug.cgi?id=217448
#regzbot title: SPI NOR bank divide by zero on Lenovo ThinkPad X1 Titanium
#regzbot fix: MTD SPI-NOR: BUG FIX of divide by zero in new n_banks value

Thanks.

[1]: https://bugzilla.kernel.org/show_bug.cgi?id=217448

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