Re: [Bug Report] [6.6] i2c: No atomic i2c transfer handler

[Tor Vic]

On 12/1/23 12:50, Dmitry Osipenko wrote:
> On 12/1/23 13:48, Tor Vic wrote:
> > Hi,
> >
> > Since Linux 6.6.3, I see some warnings in the late phase of shutdown.
> > Unfortunately, they are not logged because syslog has already shut down
> > at that point.
> >
> > I used a camera to capture a small part of the warnings:
> >
> >    No atomic I2C transfer handler for 'i2c-0'
> >    [trace follows]
> >    i2c_smbus_xfer
> >    [...]
> >
> > After checking the changelog, the culprit was found quickly:
> >
> >    (3473cf43b) i2c: core: Run atomic i2c xfer when !preemptible
> >
> > Reverting that commit made the warnings go away.
> >
> > This is a voluntary preemption kernel running on a Skylake laptop.
> >
> > Please tell me if you need more info.
>
> The warning says that I2C bus driver used by your laptop doesn't support
> atomic transfers while it should. Which driver it is?

'i2c-0' is
SMBus [0c05]: Intel Corporation Sunrise Point-LP SMBus
using 'i801_smbus' driver.

> In your case the warning is harmless, still the I2C driver likely needs
> to be improved.

That's good news, I was a little worried because of the several (I think 
it was 3 in total) large warning splats.