Re: Linux logs error: `mei_me 0000:00:16.0: cl:host=04 me=00 is not connected`

[Paul Menzel]

Dear Tomas,


Thank you for your quick response.

Am 30.03.24 um 11:50 schrieb Winkler, Tomas:
> > -----Original Message-----
> > From: Paul Menzel <pmenzel@xxxxxxxxxxxxx>
> > Sent: Friday, March 29, 2024 12:49 PM

[…]

> > On a Dell XPS 13 9360/0596KF, BIOS 2.21.0 06/02/2022 with Debian
> > sid/unstable and self-built Linux 6.9-rc1+ with one patch on top [1] and
> > KASAN enabled.
> >
> >       $ git log --no-decorate --oneline -2 a2ce022afcbb
> >       a2ce022afcbb [PATCH] kbuild: Disable KCSAN for autogenerated *.mod.c intermediaries
> >       8d025e2092e2 Merge tag 'erofs-for-6.9-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs
> >
> > After several ACPI S3 (deep) suspend and resume cycles, this morning I
> > noticed the error below:
> >
> >       [29357.177635] mei_me 0000:00:16.0: cl:host=04 me=00 is not connected
> >
> > This seems to be logged from `mei_write()` in `drivers/misc/mei/main.c`.
> >
> >       if (!mei_cl_is_connected(cl)) {
> >       	cl_err(dev, cl, "is not connected");
> >       	rets = -ENODEV;
> >       	goto out;
> >       }
> >
> > with `drivers/misc/mei/client.h` containing:
> >
> >       /**
> >        * mei_cl_is_connected - host client is connected
> >        *
> >        * @cl: host client
> >        *
> >        * Return: true if the host client is connected
> >        */
> >       static inline bool mei_cl_is_connected(const struct mei_cl *cl)
> >       {
> >       	return  cl->state == MEI_FILE_CONNECTED;
> >       }
> >
> > Unfortunately, I do not know at all, why the ME needs to be written to, and
> > what was tried to be written, and what the effect of this failure is.
> >
> > Could you please take a look at it?
>
> Looks like a timing issue between setting up HDCP by graphics and
> device power management.  I don't think this is a really an issue if
> this is happening during power cycles stress.

Understood. Could this be because of the Address Sanitizer (KASAN)?

> Anyway we will look at that, will you be able to provide more debug
> information if we ask for it?
Thank you. Yes, I can test patches. But right now, I was only able to 
see this once, so I am not sure how to reproduce it.


Kind regards,

Paul