[PATCH] machintosh: select defaults for cooling

Michael Ellerman mpe at ellerman.id.au
Mon Jul 17 12:02:29 AEST 2017

Linus Walleij <linus.walleij at linaro.org> writes:

> I have this pretty nasty problem when trying to boot up a fresh
> openSuSE DVD on a PowerMac G5: the kernel by default does not have
> CONFIG_WINDFARM_PM72 enabled, with the effect that the cooling
> is not functioning.
> The BIOS on the PowerMac G5 reacts to this by, after a grace
> period when the BIOS has waited for the OS to take over, increasing
> the fan speeds so it sounds like an airplane is in the room, and
> after another grace period simply cutting the power to the
> machine. This is done not beacuse the cooling is not working, but
> because the BIOS is not recieving handover of cooling from the
> OS, so it panics and give up. The problem has been reported by
> Linux users online.
> Needless to say, this makes it impossible to install the OS
> before the machine turns itself off.
> The g5_defconfig looks like this:
> Notably PM72 is missing, making the PowerMac G5 fail.
> The defconfig is not the right place to do this: it should be
> done by default when selecting Mac support for PPC/PPC64 and
> especially for the Macs CPUfreq driver. We select SMU by default
> for PPC_PMAC64, WINDFARM by default on PPC_PMAC and all the
> WINDFARM thermal managers by default if CPU_FREQ_PMAC64 is
> selected.

I agree with the intent of your patch, but I'm not sure I like the

> diff --git a/drivers/macintosh/Kconfig b/drivers/macintosh/Kconfig
> index 97a420c11eed..d7186d8f30a9 100644
> --- a/drivers/macintosh/Kconfig
> +++ b/drivers/macintosh/Kconfig
> @@ -101,6 +101,7 @@ config ADB_PMU_LED_DISK
>  config PMAC_SMU
>  	bool "Support for SMU  based PowerMacs"
>  	depends on PPC_PMAC64
> +	default PPC_PMAC64

Defaulting to one of your dependencies is exactly the same as defaulting
to yes (unless it's a tristate).

I think it's fine to make this default y, it has the dependency on the
platform so it won't appear for most users.

> @@ -194,11 +195,13 @@ config THERM_ADT746X
>  config WINDFARM
>  	tristate "New PowerMac thermal control infrastructure"
>  	depends on PPC
> +	default PPC_PMAC
>  config WINDFARM_PM81
>  	tristate "Support for thermal management on iMac G5"
>  	depends on WINDFARM && I2C && CPU_FREQ_PMAC64 && PMAC_SMU
>  	select I2C_POWERMAC
> +	default CPU_FREQ_PMAC64
>  	help
>  	  This driver provides thermal control for the iMacG5

These I think should all just be 'default m'.


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