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

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Date: Fri, 29 Mar 2024 10:48:45 +0100
From: Paul Menzel <pmenzel@...gen.mpg.de>
To: Tomas Winkler <tomas.winkler@...el.com>
Cc: LKML <linux-kernel@...r.kernel.org>
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?


Kind regards,

Paul


[1]: 
https://lore.kernel.org/all/20240326202548.GLZgMvTGpPfQcs2cQ_@fat_crate.local/
View attachment "20240328--dell-xps-13-9360--linux-6.9-rc1+--messages.txt" of type "text/plain" (204896 bytes)