Bug#1107824: x11-xserver-utils: xrandr does not anymore correctly detect an HDMI monitor over a usb-c adapter

[ale <ale.comp_06@xox.ch>]

Package: x11-xserver-utils
Version: 7.7+11
Severity: important
X-Debbugs-Cc: ale.comp_06@xox.ch

Dear Maintainer,

On Debian Testing, since an update about a month ago, I cannot connect to my HDMI monitor through any of my two USB-C adapters.

Currently:

- Directly connecting through HDMI does work.
- Using another (very similar) Laptop with outdated packages still works as expected with the same USB C adapter and monitor.


When attatching the monitor through the USB C adapter, `xrandr -q` (and lxrandr) do not correctly report the monitor anymore:

```
DisplayPort-0 connected (normal left inverted right x axis y axis)
   1024x768      60.00
   832x624       74.55
   800x600       72.19    75.00    60.32    56.25
   720x576       50.00
   720x480       60.00    59.94
   640x480       75.00    72.81    66.67    60.00    59.94
   720x400       70.08
```

These are the values shown by `xrandr -q` when directly connecting through the HDMI port:

```
HDMI-A-0 connected (normal left inverted right x axis y axis)
   2560x1440     59.95 +  74.97
   1920x1200     59.95
   1920x1080     74.97    60.00    50.00    59.94
   1600x1200     59.95
   1680x1050     59.88
   1280x1024     75.02    60.02
   1440x900      59.90
   1280x960      60.00
   1280x800      59.95
   1280x720      60.00    50.00    59.94
   1024x768      75.03    70.07    60.00
   832x624       74.55
   800x600       72.19    75.00    60.32    56.25
   720x576       50.00
   720x480       60.00    59.94
   640x480       75.00    72.81    66.67    60.00    59.94
   720x400       70.08
```

When applying the _wrong_ DisplayPort-0 in `lxrandr`, I only get a single line message in `dmesg`:

```
amdgpu 0000:05:00.0: [drm] enabling link 2 failed: 15
```

And nothing shows on the HDMI monitor.


On the older laptop, with the monitor connected through the USB C adpater, xrandr reports:

```
DisplayPort-0 connected 2560x1440+1920+0 (normal left inverted right x axis y axis) 527mm x 296mm
   2560x1440     59.95*+  74.97
   1920x1200     59.95
   1920x1080     74.97    60.00    50.00    59.94
   1600x1200     59.95
   1680x1050     59.88
   1280x1024     75.02    60.02
   1440x900      59.90
   1280x960      60.00
   1280x800      59.95
   1280x720      60.00    50.00    59.94
   1024x768      75.03    70.07    60.00
   832x624       74.55
   800x600       72.19    75.00    60.32    56.25
   720x576       50.00
   720x480       60.00    59.94
   640x480       75.00    72.81    66.67    60.00    59.94
   720x400       70.08
DisplayPort-1 disconnected (normal left inverted right x axis y axis)
```

and everything works fine.

-- System Information:
Debian Release: 13.0
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 6.12.27-amd64 (SMP w/12 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF8, LC_CTYPE=en_US.UTF8 (charmap=UTF-8), LANGUAGE=en_US.UTF8
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages x11-xserver-utils depends on:
ii  cpp          4:14.2.0-1
ii  libc6        2.41-8
ii  libice6      2:1.1.1-1
ii  libx11-6     2:1.8.12-1
ii  libxaw7      2:1.0.16-1
ii  libxcursor1  1:1.2.3-1
ii  libxext6     2:1.3.4-1+b3
ii  libxi6       2:1.8.2-1
ii  libxmu6      2:1.1.3-3+b4
ii  libxmuu1     2:1.1.3-3+b4
ii  libxrandr2   2:1.5.4-1+b3
ii  libxt6t64    1:1.2.1-1.2+b2
ii  libxxf86vm1  1:1.1.4-1+b4

x11-xserver-utils recommends no packages.

Versions of packages x11-xserver-utils suggests:
pn  cairo-5c        <none>
pn  nickle          <none>
ii  xorg-docs-core  1:1.7.3-1

-- no debconf information