#1075770 linux-image-6.9.7-amd64: adlp_tc_phy_connect [i915] fills logs with drm_WARN_ON(tc->mode == TC_PORT_LEGACY) call traces

Package:
src:linux
Source:
src:linux
Submitter:
Francesco Poli (wintermute)
Date:
2025-08-10 19:13:05 UTC
Severity:
normal
Tags:
#1075770#5
Date:
2024-07-04 17:36:21 UTC
From:
To:
Hello,
on a laptop where I installed Debian testing some 6 months ago,
I noticed that the logs are continuously filled with call traces
like the attached snippet (taken from /var/log/kern.log ).

It seems to me that it also used to happen with previous versions
of the Linux kernel, but I am under the impression that, with linux/6.9.7-1,
it got worse.

I see 12 of these call traces just after boot, before even starting X
(with 'startx').
More of these call traces are sent to the logs after starting X, or
after invoking 'xrandr', or after locking the X session (with
XScreenSaver), ...

They seem to correspond to no actual issue, as far as I can tell,
but they are filling the logs with a significant flow of text...
which is worrying by itself.

What's wrong?
How can I stop this log-filling flood?

#1075770#10
Date:
2024-07-13 13:04:49 UTC
From:
To:
Hi Francesco,

We discussed your case in the last kernel-team meeting and came to the
conclusion that if possible you report your issue upstream and keep us
here in the loop about progressm. I was not clear though if you need
some guidance to do so.

The get the correct contact addresses for reporting the issue you can
use the get_maintainers.pl script in the upstream source. I would
suggest to approach the following people:

$ ./scripts/get_maintainer.pl drivers/gpu/drm/i915/display/intel_tc.c
Jani Nikula <jani.nikula@linux.intel.com> (supporter:INTEL DRM DISPLAY FOR XE AND I915 DRIVERS)
Rodrigo Vivi <rodrigo.vivi@intel.com> (supporter:INTEL DRM DISPLAY FOR XE AND I915 DRIVERS)
Joonas Lahtinen <joonas.lahtinen@linux.intel.com> (supporter:INTEL DRM I915 DRIVER (Meteor Lake, DG2 and old...)
Tvrtko Ursulin <tursulin@ursulin.net> (supporter:INTEL DRM I915 DRIVER (Meteor Lake, DG2 and old...)
David Airlie <airlied@gmail.com> (maintainer:DRM DRIVERS)
Daniel Vetter <daniel@ffwll.ch> (maintainer:DRM DRIVERS)
intel-gfx@lists.freedesktop.org (open list:INTEL DRM DISPLAY FOR XE AND I915 DRIVERS)
intel-xe@lists.freedesktop.org (open list:INTEL DRM DISPLAY FOR XE AND I915 DRIVERS)
dri-devel@lists.freedesktop.org (open list:DRM DRIVERS)
linux-kernel@vger.kernel.org (open list)

Regards,
Salvatore

#1075770#15
Date:
2024-07-13 17:10:08 UTC
From:
To:
On Sat, 13 Jul 2024 15:04:49 +0200 Salvatore Bonaccorso wrote:

[...]
[...]

Wouldn't it be so much easier, if you just forward my bug report
upstream?

#1075770#20
Date:
2024-07-13 18:56:08 UTC
From:
To:
Hi,

You are directly affected and we cannot reproduce the issue on our
own, so we gave you guidance on where exactly to report it. If you
directly report it you get the direct interaction with upstream, as
you might be the only one providing additional feedback on question.

But sure if you do not want to report it, I can forward to the
maintainers with similar effect, just let me know if you prefer to not
write on your own to upstream.

Regards,
Salvatore

#1075770#27
Date:
2024-07-15 18:20:46 UTC
From:
To:
On Sat, 13 Jul 2024 20:56:08 +0200 Salvatore Bonaccorso wrote:

[...]
[...]

OK, I'll try, but, depending on which feedback I am asked to provide,
I could need some help from you.

#1075770#32
Date:
2024-07-15 18:35:43 UTC
From:
To:
Hi all,
on a laptop where I installed Debian testing some 6 months ago,
I noticed that the logs are continuously flooded with call traces
like the attached snippet (taken from /var/log/kern.log ).

It seems to me that it also used to happen with previous versions
of the Linux kernel, but I am under the impression that, with Linux
kernel 6.9.7, it got worse. I have recently upgraded to Linux kernel
version 6.9.8 (provided by the distro, Debian testing, as I said), but
the bug is still reproducible:

  $ uname -srvmo
  Linux 6.9.8-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.9.8-1 (2024-07-07) x86_64 GNU/Linux

I see at least 12 of these call traces just after boot, before even
starting X (with 'startx').
More of these call traces are sent to the logs after starting X, or
after invoking 'xrandr', or after locking the X session (with
XScreenSaver), ...
I always see these call traces (I mean the bug is always reproducible:
each time I boot, each time I call xrandr, ...).

They seem to correspond to no actual issue, as far as I can tell,
but they are flooding the logs with a significant flow of text...
which is worrying by itself.


What's wrong?
How can I stop this log-filling flood?
Should I black-list some module, for instance?


The outputs of

  # lspci -vnn -d :*:0300

and of

  # dmidecode

are attached.
Also, I booted with kernel parameters
'drm.debug=0xe log_buf_len=4M ignore_loglevel' and
logged in as root right after the boot.
The output of

  # dmesg

is attached.

Some additional information may be found on the [Debian bug] report I had previously filed.

[Debian bug]: <https://bugs.debian.org/1075770>


N.B.:
Please Cc me and the Debian bug address <1075770@bugs.debian.org>
on replies, so that the interested parties (including me!) are kept
in the loop.
Thanks a lot for your time and for any help you may provide!

#1075770#43
Date:
2024-07-24 16:02:16 UTC
From:
To:
Please file i915 bugs at fdo gitlab as described at [1].

BR,
Jani.

[1] https://drm.pages.freedesktop.org/intel-docs/how-to-file-i915-bugs.html

#1075770#48
Date:
2024-07-24 18:30:00 UTC
From:
To:
and 3 legacy DP connectors (the latter 3 being a bit odd on a laptop,
even if not impossible). The DMI in BIOS says:

DMI: Notebook NLxxPUx/NLxxPUx, BIOS 1.07.09 11/17/2023

for which I can't find the particular system to check the actual
configuration. Could you point to the laptop vendor/model's page or
describe what are the connectors on it?

Could you check if there is a BIOS upgrade available? Please follow up
on the gitlab issue as Jani suggested.

#1075770#53
Date:
2024-07-25 21:59:29 UTC
From:
To:
On Wed, 24 Jul 2024 21:30:00 +0300 Imre Deak wrote:

[...]

Thanks to you for looking into them!
By the way, I have just upgraded the Linux kernel, but the
issue stays the same:

  $ uname -srvmo
  Linux 6.9.10-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.9.10-1 (2024-07-19) x86_64 GNU/Linux

which I think it has (and dmidecode seems to see it)...

Do you mean that I should see 3 external DisplayPort connectors?
I really cannot spot them.
I cannot see any set of three identical connectors on the "outer
surface" of the laptop case, actually.

However, the graphics software stack sees them, as confirmed by
the output of 'xrandr' (attached).

Could they be internal (unused) connectors?

Or maybe they are not really present in the hardware, and the Linux
kernel wrongly thinks they are there, because of some bug...?
Could this happen?!?

The label on the bottom of the laptop case says:

  MODEL: NL41PU

and

  PRODUCT CODE: NL41PU2

According to the same label, the brand should be [Clevo].

[Clevo]: <https://clevo-computer.com/en/>

I bought the laptop from an Italian shop which, among other things,
assembles customized laptops, that can be configured through
a web [configurator] (unfortunately, it seems that the website
is in Italian only...).

[configurator]: <https://syspack.com/configuratoreNotebook.php>

The notebook that I selected (along with other components) is
identified as "Work14 i5-1235U DDR4 M.2 14" FullHD"
The provided description (translated into English by me) is attached.

I think the Clevo NL41PU laptop is the same as the one
described [here].

[here]: <https://laptopwithlinux.com/product/clevo-nl41/>
the relevant download server [folder], but it seems to me that
there is no upgrade later than "1.07.09 11/17/2023"...
Actually, I cannot even see that version, which is awkward.
Maybe I am misunderstanding something...   :-(
Or maybe not: I have also asked the shop about possible BIOS upgrades,
and they replied to me that there are no BIOS upgrades yet for that
model, as far as they can tell.

[support]: <https://clevo-computer.com/en/support-drivers>
[folder]: <https://my.hidrive.com/share/yze8mg-wf8#$/BIOS%20and%20EC%20Firmware/CLEVO/N_Series/NLxxx/NLxxPxx/NL4xPUx>

I had reported the bug to the Debian BTS (Bug Tracking System), where
I was told to report the bug upstream, by contacting developers/mailing
lists.
Now on this mailing list, I am being told to report the issue on
gitlab.freedesktop.org (which requires to register an account, in order
to report issues)... Having to jump through all these hoops is beginning
to be a little time consuming...   :-(

#1075770#58
Date:
2024-07-29 10:19:06 UTC
From:
To:
There are a number of reasons why email and mailing lists are really bad
for reporting bugs, from our perspective, which is why we've asked
people to report bugs to freedesktop.org bug trackers for about a decade
now.

If the right person doesn't have time to resolve the issue right away,
it'll likely be forgotten on the mailing list. Attachments aren't
welcome on mailing lists, let alone big logs. It's easier to label and
reference issues on a bug tracker. It's easier (yes, for us) to manage
the issues, and the people working on them, on a bug tracker. And so on.

BR,
Jani.

#1075770#63
Date:
2024-10-29 07:47:51 UTC
From:
To:
On Mon, 29 Jul 2024 13:19:06 +0300 Jani Nikula wrote:

[...]

I filed an issue report on the freedesktop.org tracker (however, there
have been no replies yet).

I still experience the bug with:

$ uname -srvmo
Linux 6.11.4-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.11.4-1 (2024-10-20) x86_64 GNU/Linux

#1075770#72
Date:
2024-12-05 19:33:04 UTC
From:
To:
This is actually really easy to reproduce. Any N100 or N97 cpu will also
have this bug. I cannot recompile the kernel to test the latest drm-tip
though, but if someone else on this mailing list can, we would appreciate
it if you would post your findings on the gitlab bug
https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/12246

Either that or maybe suggest a PPA Ubuntu kernel repo that has a newer
version of drm-tip that we can test

Cheers
Angelo