linux-kernel - Re: [PATCH] rtc: report time-retrieval errors when updating alarm

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Message-ID: <20191021174809.GA3125@piout.net>
Date:   Mon, 21 Oct 2019 19:48:09 +0200
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Brian Norris <briannorris@...omium.org>
Cc:     Alessandro Zummo <a.zummo@...ertech.it>, linux-rtc@...r.kernel.org,
        Linux Kernel <linux-kernel@...r.kernel.org>,
        Jeffy Chen <jeffy.chen@...k-chips.com>,
        Matthias Kaehlcke <mka@...omium.org>
Subject: Re: [PATCH] rtc: report time-retrieval errors when updating alarm

On 21/10/2019 10:20:08-0700, Brian Norris wrote:
> Hi Alexandre!
> 
> On Mon, Oct 21, 2019 at 9:11 AM Alexandre Belloni
> <alexandre.belloni@...tlin.com> wrote:
> > On 21/05/2018 09:42:22-0700, Brian Norris wrote:
> > > __rtc_read_time() can fail (e.g., if the RTC uses an unreliable medium).
> > > When it does, we don't report the error, but instead calculate a
> > > 1-second alarm based on the potentially-garbage 'tm' (in practice,
> > > __rtc_read_time() zeroes out the time first, so it's likely to still be
> > > all 0).
> > >
> > > Let's propagate the error instead.
> > >
> >
> > I submitted
> > https://lore.kernel.org/linux-rtc/20191021155631.3342-2-alexandre.belloni@bootlin.com/T/#u
> > to solve this after looking at all the implication checking the return
> > value of __rtc_read_time had.
> 
> Only about a year and a half late, nice!

I know, right? :) The fact is that this is not a common issue or at
least, I didn't have any report that this was causing real problems in
the field. So it ended up being one of the longest standing patch in
patchwork...

>Fortunately we have a decent
> (albeit time-consuming) process for rebasing our downstream patches in
> Chrome OS kernels...
> 

Do you need that patch backported to LTS kernels?


-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com