linux-kernel - Re: [PATCH 1/1] efi: rtc: Enable SET/GET WAKEUP services as optional

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Message-ID: <CAMj1kXHAYvGdGJN0rfEL2y1jRP8P5YotKMmCmx0h07vJP=YfBA@mail.gmail.com>
Date:   Tue, 3 Jan 2023 10:18:06 +0100
From:   Ard Biesheuvel <ardb@...nel.org>
To:     Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc:     Shanker Donthineni <sdonthineni@...dia.com>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        linux-rtc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-efi@...r.kernel.org
Subject: Re: [PATCH 1/1] efi: rtc: Enable SET/GET WAKEUP services as optional

On Mon, 2 Jan 2023 at 23:21, Alexandre Belloni
<alexandre.belloni@...tlin.com> wrote:
>
> On 02/01/2023 11:47:11+0100, Ard Biesheuvel wrote:
> > On Tue, 27 Dec 2022 at 05:09, Shanker Donthineni <sdonthineni@...dia.com> wrote:
> > >
> > > The current implementation of rtc-efi is expecting all the 4
> > > time services GET{SET}_TIME{WAKEUP} must be supported by UEFI
> > > firmware. As per the EFI_RT_PROPERTIES_TABLE, the platform
> > > specific implementations can choose to enable selective time
> > > services based on the RTC device capabilities.
> > >
> > > This patch does the following changes to provide GET/SET RTC
> > > services on platforms that do not support the WAKEUP feature.
> > >
> > > 1) Relax time services cap check when creating a platform device.
> > > 2) Clear RTC_FEATURE_ALARM bit in the absence of WAKEUP services.
> > > 3) Conditional alarm entries in '/proc/driver/rtc'.
> > >
> > > Signed-off-by: Shanker Donthineni <sdonthineni@...dia.com>
> >
> > Queued as a fix in efi/urgent, thanks.
>
> This rather seems like an rtc heavy patch and the subject line is
> misleading. This should be rtc: efi:
> Also, I'm pretty sure this doesn't qualify as an urgent fix.
>

I'm happy to drop it from my tree, but please add a cc:stable so it
gets backported to v6.1 at least. Otherwise, EFI compliant systems
that implement get/set_time but not get/set_wakeup_time have no RTC at
all on any LTS kernel until a year from now, and this was never the
intent when we introduced the EFI_RT_PROPERTIES_TABLE.