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

[Winkler, Tomas]

> -----Original Message-----
> From: Paul Menzel <pmenzel@xxxxxxxxxxxxx>
> Sent: Friday, March 29, 2024 12:49 PM
> To: Winkler, Tomas <tomas.winkler@xxxxxxxxx>
> Cc: LKML <linux-kernel@xxxxxxxxxxxxxxx>
> Subject: Linux logs error: `mei_me 0000:00:16.0: cl:host=04 me=00 is not
> connected`
> 
> Dear Linux folks,
> 
> 
> 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.  Anyway we will look at that, will you be able to provide more debug information if we ask for it?

Thanks
Tomas