linux-kernel - Re: [PATCH 1/3] hwmon: spd5118: Do not fail resume on temporary I2C errors

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAJ12PfNkde6__QQXMiyBbEoHMbY3efmtsqgbyiKBtBmyfpX5Jw@mail.gmail.com>
Date: Tue, 13 Jan 2026 22:15:26 +0300
From: TINSAE TADESSE <tinsaetadesse2015@...il.com>
To: Guenter Roeck <linux@...ck-us.net>
Cc: linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] hwmon: spd5118: Do not fail resume on temporary I2C errors

On Mon, Jan 12, 2026 at 7:30 PM Guenter Roeck <linux@...ck-us.net> wrote:
>
> On 1/10/26 09:19, Tinsae Tadesse wrote:
> > SPD5118 DDR5 temperature sensors may be temporarily unavailable
> > during s2idle resume. Ignore temporary -ENXIO and -EIO errors during resume and allow
> > register synchronization to be retried later.
> >
> > Signed-off-by: Tinsae Tadesse <tinsaetadesse2015@...il.com>
> > ---
> >   drivers/hwmon/spd5118.c | 8 +++++++-
> >   1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/hwmon/spd5118.c b/drivers/hwmon/spd5118.c
> > index 5da44571b6a0..ec9f14f6e0df 100644
> > --- a/drivers/hwmon/spd5118.c
> > +++ b/drivers/hwmon/spd5118.c
> > @@ -512,9 +512,15 @@ static int spd5118_resume(struct device *dev)
> >   {
> >       struct spd5118_data *data = dev_get_drvdata(dev);
> >       struct regmap *regmap = data->regmap;
> > +     int ret;
> >
> >       regcache_cache_only(regmap, false);
> > -     return regcache_sync(regmap);
> > +     ret = regcache_sync(regmap);
> > +     if(ret == -ENXIO || ret == -EIO) {
> > +             dev_warn(dev, "SPD hub not responding on resume (%d), deferring init\n", ret);
> > +             return 0;
> > +     }
> > +     return ret;
> >   }
> >
> >   static DEFINE_SIMPLE_DEV_PM_OPS(spd5118_pm_ops, spd5118_suspend, spd5118_resume);
>
>
> Based on the subsequent exchange, this is not the appropriate solution.
> The problem is that the i2c controller suspends too early. It should suspend
> later instead. Alternatively, this driver should suspend early, but it does
> not look like respective PM operations are available.
>
> I would suggest to try replacing DEFINE_SIMPLE_DEV_PM_OPS() in drivers/i2c/busses/i2c-i801.c
> with SET_LATE_SYSTEM_SLEEP_PM_OPS() or similar.
>
> Guenter
>

Hi Guenter,

I tested changing the i801 SMBus controller to use
SET_LATE_SYSTEM_SLEEP_PM_OPS() instead of
DEFINE_SIMPLE_DEV_PM_OPS() as a diagnostic experiment. With this
change, spd5118 resume failures (-ENXIO)
still persist, suggesting PM ordering alone is insufficient and other
firmware interactions are involved.