Re: [RFC PATCH v3 5/5] arm64: Use SYSTEM_OFF2 PSCI call to power off for hibernate

From: Marc Zyngier
Date: Fri Mar 22 2024 - 12:02:31 EST


On Tue, 19 Mar 2024 12:59:06 +0000,
David Woodhouse <dwmw2@xxxxxxxxxxxxx> wrote:

[...]

> +static void __init psci_init_system_off2(void)
> +{
> + int ret;
> +
> + ret = psci_features(PSCI_FN_NATIVE(1_3, SYSTEM_OFF2));
> +
> + if (ret != PSCI_RET_NOT_SUPPORTED)
> + psci_system_off2_supported = true;

It'd be worth considering the (slightly broken) case where SYSTEM_OFF2
is supported, but HIBERNATE_OFF is not set in the response, as the
spec doesn't say that this bit is mandatory (it seems legal to
implement SYSTEM_OFF2 without any hibernate type, making it similar to
SYSTEM_OFF).

Thanks,

M.

--
Without deviation from the norm, progress is not possible.