[BUG] Rockchip SPI: Runtime PM usage count underflow!

[Vicente Bergas]

On Mon, Aug 19, 2024 at 4:12 AM Vicente Bergas <vicencb at gmail.com> wrote:
>
> On Sun, Aug 18, 2024 at 8:13 PM Vicente Bergas <vicencb at gmail.com> wrote:
> >
> > Hi,
> > i am a user of the CONFIG_SPI_SPIDEV device.
> > It stopped working between 6.8 and 6.10.5.
> > The SPI bus itself reports no errors to userspace, but no devices
> > appear connected to the bus.
> > The platform used is RK3328.
> > The only spi-related message in dmesg is:
> > rockchip-spi ff190000.spi: Runtime PM usage count underflow!
> >
> > Please, can somebody review this issue?
> >
> > Regards,
> >   Vicente.
>
> I've tried to bisect, but there is some strange behaviour:
> The message "Runtime PM usage count underflow!" can also appear on a
> good kernel.
> In order to have a reasoble iteration speed, i am updating the kernel via kexec.
> If a good kernel (6.6.30) is cold-booted, then, all the kernels
> kexec'd from it work too.
> If a bad kernel (6.10.5) is cold-booted, then a 6.6.30 is kexec'd and
> then the same 6.10.5 is kexec'd it becomes a good one.

Added:
Huang-Huang Bao <i at eh5.me>
Linus Walleij <linus.walleij at linaro.org>
Sasha Levin <sashal at kernel.org>

The first offending commit is:
29d8101fb9442544077e68e27839a1979f85633d pinctrl: rockchip: fix pinmux
bits for RK3328 GPIO2-B pins

I've also tested 6.10.6 with it reverted (and
456447ff1fe3c28e2fd7b57a79650f62245c6428 and
7127c68c76f120367b9a5053f524df0b603d4a48 as dependencies) and SPI
works fine.

Regards,
  Vicente.