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Message-ID: <9a0551c8-d29e-4fb8-a85e-6f7f72e0de69@molgen.mpg.de>
Date: Sat, 30 Mar 2024 11:56:17 +0100
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Subject: Re: Linux logs error: `mei_me 0000:00:16.0: cl:host=04 me=00 is not
 connected`
To: Tomas Winkler <tomas.winkler@intel.com>,
 Alexander Usyskin <alexander.usyskin@intel.com>
Cc: LKML <linux-kernel@vger.kernel.org>
References: <4c785706-2961-4eac-b5d7-2cf89c195969@molgen.mpg.de>
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From: Paul Menzel <pmenzel@molgen.mpg.de>
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Dear Tomas,


Thank you for your quick response.

Am 30.03.24 um 11:50 schrieb Winkler, Tomas:
> 
>> -----Original Message-----
>> From: Paul Menzel <pmenzel@molgen.mpg.de>
>> 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