linux-kernel - Re: [PATCH 0/7] rtc: Add support for limited alarm timer offsets

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Message-ID: <6ffc915e-ca91-4b64-b7a5-f13f60df8b1d@roeck-us.net>
Date:   Wed, 16 Aug 2023 12:12:14 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc:     Alessandro Zummo <a.zummo@...ertech.it>,
        Benson Leung <bleung@...omium.org>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        John Stultz <jstultz@...gle.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-rtc@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Brian Norris <briannorris@...omium.org>
Subject: Re: [PATCH 0/7] rtc: Add support for limited alarm timer offsets

On Wed, Aug 16, 2023 at 06:14:35PM +0200, Alexandre Belloni wrote:
> On 16/08/2023 08:50:12-0700, Guenter Roeck wrote:
> > > I'm fine with the series, however, this doesn't solve the issue for RTCs
> > > that have an absolute limit on the alarm (as opposed to an offset to the
> > > current time/date).
> > > 
> > 
> > I thought that is checked by rtc_valid_range() in rtc_set_alarm().
> > Am I missing something ? Of course that assumes that the absolute
> > maximum alarm timeout matches range_max, but I didn't find any
> > drivers where that would not be the case.
> > 
> 
> There are RTCs where this is not the case. When this is far away in the
> future enough, the usual solution is to clip range_max which works but
> is not really great intellectually.
> 
Do you have an example, by any chance ?

Thanks,
Guenter

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