Re: [PATCH v6 0/2] soc: loongson2_pm: add power management support

Arnd Bergmann
2023-08-22T01:04:28Z

On Thu, Aug 3, 2023, at 02:37, Yinbo Zhu wrote:
> Loongson-2 platform support Power Management Controller (ACPI) and this
> series patch was to add PM driver that base on dts and PM binding support.
>
> Change in v6:
> 1. The patch "[PATCH v3 1/3] loongarch: export some arch-specific
> pm interfaces" had been merged into mainline tree in v6.5-rc1
> thus this v6 series patch need drop it and need depend on it
> and it's patch link was:
> https://lore.kernel.org/all/20230615091757.24686-2-zhuyinbo@loongson.cn/
> 2. Adding Ulf Hansson to Cc.
> 3. Adding soc@kernel.org to Cc.
> 4. Keep indented with one tab +2 spaces in Kconfig help text.

I talked to WANG Xuerui on IRC, and he was able to clarify some of the
missing bits of information for me, after which I merged both patches,
even though my concerns are not fully addressed:

- I still think that branching into ROM code from the kernel is a mistake
and we should have never allowed that as an ad-hoc interface in the ACPI
variant to start with. It's hard to change that now though, and having
a DT interface to access the same entry point does not really make it
worse. This might need a redesign for future firmware though, to have
a proper runtime interface

- The bigger problem I still see is the DT-enabled boot with PMon without
the UEFI firmware. This does not impact the DT binding, but I would
consider all non-UEFI booting firmware images broken and not supported
by the kernel, as we originally discussed when merging the kernel.
These should still be fixable by upgrading PMon to a UEFI-enabled
version.

Arnd