Re: [PATCH] arm64: dts: qcom: sc8280xp-blackrock: switch to uefi rtc offset

From: Konrad Dybcio
Date: Mon Jan 27 2025 - 05:24:22 EST


On 22.01.2025 7:41 AM, Jens Glathe via B4 Relay wrote:
> From: Jens Glathe <jens.glathe@xxxxxxxxxxxxxxxxxxxxxx>
>
> On many Qualcomm platforms the PMIC RTC control and time registers are
> read-only so that the RTC time can not be updated. Instead an offset
> needs be stored in some machine-specific non-volatile memory, which a
> driver can take into account.
>
> Switch to using the Qualcomm specific UEFI variable that is used by the
> UEFI firmware (and Windows) to store the RTC offset.
>
> This specifically means that the RTC time will be synchronised between
> the UEFI firmware setup (or UEFI shell), Windows and Linux.
>
> Note however that Windows stores the RTC time in local time by default,
> while Linux typically uses UTC (i.e. as on X86).
>
> Based on a patch by Johan Hovold. [1]
>
> Link: https://lore.kernel.org/all/20250120144152.11949-7-johan+linaro@xxxxxxxxxx/ # [1]
> Signed-off-by: Jens Glathe <jens.glathe@xxxxxxxxxxxxxxxxxxxxxx>
> ---

Reviewed-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>

Konrad