Re: [PATCH] mfd/rk8xx: fix sleep during RCU read side critical section

[Eric Anderson]

Pavel,

I tested the patch, and it didn't impact shutdown/restart of my Veyron
device (it continued working properly).

On Fri, Oct 30, 2026 at 7:44 AM Pavel Skripkin <paskripkin@xxxxxxxxx> wrote:
> Based on code I believe that it was indeed broken from the beginning.
> Also I've found previous attempt to fix it [1], so looks like problem is
> known for quite a long time

So Sebastian noticed the i2c regression due to his earlier change. But
spi wasn't actually broken when using SYS_OFF_MODE_POWER_OFF (as the
code is now); the board still powered down, just with the WARNING
noise. The thread on lore[1] is easier to follow, as it isn't split
into months.

In the thread, the feeling is the approach is a hack, because you
don't actually want to poweroff during _PREPARE. And Lee is concerned
about the hack:
> What's the bet that if accepted, this hack is still here in 5 years time?

The main argument for using _PREPARE for SPI is that it is a small,
simple workaround and could go in the LTS. Interestingly, because that
patch wasn't accepted, the hack continued living and i2c suffered. My
change then removed the spi hack.

1. https://lore.kernel.org/all/20240730180903.81688-1-sebastian.reichel@xxxxxxxxxxxxx/