Re: [BUG] hwmon: (spd5118) resume fails -ENXIO on write protected hubs

[Guenter Roeck]

On 8/17/26 09:42, GG wrote:
> Sorry - I should have searched the archives before sending my last email. I've since
> found this from February, which is the same problem:
>
>    https://lore.kernel.org/linux-hwmon/20260205102942.28745-1-tinsaetadesse2015@xxxxxxxxx/
>
> And I missed the obvious clue sitting in my own boot log:
>
>    i801_smbus 0000:00:1f.4: SPD Write Disable is set
>
> So my kernel already knew. Apologies for the noise.

Unfortunately that knowledge is not passed on to the spd5118 driver.

> One thing I'll mention in case it's useful: that series above has spd5118 refuse to
> probe when writes are disabled. On my machine that would lose me two working
> temperature sensors. Reads are completely fine here, I get correct temps,
> and my temperature limits read back properly. It's only writing that fails.
>
> Happy to test anything on my hardware if it would help.

That can not be done, as I mentioned in my other e-mail.

Problem is that accessing temperature sensor data on spd5118 compatible chips
requires a write to select the correct chip page. If writes are disabled, and
the BIOS selected a page other than page 0, temperature sensor data is not
accessible. Since the BIOS can do whatever it wants and may have selected a
different page after a suspend/resume sequence, one simply can not trust
the status when the driver is loaded initially.

Guenter