Re: [PATCH v12 1/1] serial: core: Start managing serial controllers to enable runtime PM

[Chen-Yu Tsai]

On Tue, Jun 6, 2023 at 8:21 PM Tony Lindgren <tony@xxxxxxxxxxx> wrote:
>
> * Chen-Yu Tsai <wenst@xxxxxxxxxxxx> [230606 09:17]:
> > I ended up following 8250_dw's design, which seemed less convoluted.
> > The original code was waaay too convoluted.
>
> OK that looks good to me thanks. Good to hear you got it sorted out.
>
> The 8250_dw style runtime PM is a good solution for simple cases. Where
> it won't work are SoCs where runtime PM calls need to propagate up the
> bus hierarchy. For example, 8250_omap needs runtime PM calls for the
> interconnect and power domain to get register access working.

Good to know. On MediaTek platforms I don't think there are any power
domains covering the basic peripherals. (Or it's hidden from the kernel.)

> > BTW, the Bluetooth breakage seems like a different problem.
>
> OK seems like we're good to go then :)

Yup. After a bit more testing, it seems the Bluetooth problem is more like
an undervolt issue. If I have WiFi and BT probe at the same time, Bluetooth
fails. If they probe separately, everything works fine.

ChenYu