[Bug 2112518] Re: [AMDGPU] No display during boot on AMDGPU system with Thunderbolt-connected monitor

Hi @juliank, thank you for the heads-up.

I just ran a test using Plucky linux-image-6.14.0-24-generic and linux-
firmware 20250317.git1d4c88ee-0ubuntu1.3, there is no regression. Update
the tag to verification-done-plucky accordingly.

** Tags removed: verification-needed-plucky
** Tags added: verification-done-plucky

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https://bugs.launchpad.net/bugs/2112518

Title:
[AMDGPU] No display during boot on AMDGPU system with Thunderbolt-
connected monitor

Status in HWE Next:
New
Status in linux package in Ubuntu:
Won't Fix
Status in linux-firmware package in Ubuntu:
In Progress
Status in linux-oem-6.14 package in Ubuntu:
Invalid
Status in linux source package in Noble:
Won't Fix
Status in linux-firmware source package in Noble:
Fix Committed
Status in linux-oem-6.14 source package in Noble:
Fix Committed
Status in linux source package in Oracular:
Won't Fix
Status in linux-firmware source package in Oracular:
Won't Fix
Status in linux-oem-6.14 source package in Oracular:
Invalid
Status in linux source package in Plucky:
Won't Fix
Status in linux-firmware source package in Plucky:
Fix Committed
Status in linux-oem-6.14 source package in Plucky:
Invalid

Bug description:
SRU Justification:

[Impact]
On HP AMDGPU platform running the 6.14.0-1005-oem kernel, the monitor screen never appeared when booting the system with a Thunderbolt cable connected. However, we were still able to SSH into the system, suggesting that it had booted successfully.

For the Noble and Plucky generic kernels, they have been classified as
"won't fix" since the bug only occurrs on a specific platform. For
users on that platform, we recommend using our Noble 6.14-OEM kernel,
which includes the appropriate fix.

[Fix]
Updates are required for both the Linux AMDGPU driver and the linux-firmware package.

- Linux AMDGPU driver: cherry-pick the following commit from the Linux
mainline:

59510792baa drm/amd/display: Assign preferred stream encoder instance
to dpia

- linux-firmware: backport the following commits from the upstream
linux-firmware repository:

1. b3049665a5d amdgpu: DMCUB updates for various AMDGPU ASICs
2. 61d257d5a8b amdgpu: DMCUB updates for various ASICs
3. 5602c7293e6 amdgpu: DMCUB updates for various ASICs
4. b0e96674082 amdgpu: DMCUB updates for various ASICs
5. a2aaefe5a59 amdgpu: update dcn 3.5 firmware to 0.1.0.0
6. a80a8bd73e0 amdgpu: update dcn 3.5 and dcn 3.5.1 firmware to 9.0.27.0
7. 25750add9b7 amdgpu: DMCUB updates for various ASICs
8. 5ac6303062 amdgpu: DMCUB updates for various ASICs

Be aware that only amdgpu/dcn_3_5_1_dmcub.bin and amdgpu/dcn_3_5_dmcub.bin are updated by the above commits.
Updates to other files were intentionally omitted.

[Test Plan]
========= On Noble 6.14-OEM ==================
- Prerequisites:
1. Install the linux-oem-6.14 version 6.14.0-1006.6 kernel from -proposed [1]
2. Install the linux-firmware version 20240318.git3b128b60-0ubuntu2.14 from -proposed [1]

- Test instructions:
1. Connect the machine to an external monitor using a Thunderbolt cable before booting.
2. Boot the system using the Noble 6.14.0-1005-oem kernel
3. Verify that the display output appears on the monitor and the GNOME desktop environment is visible.

========= On Noble/Plucky generic ==================
- Prerequisites:
1. Install the Noble or Plucky generic kernel
2. If you will be running the Noble generic kernel, please install the linux-firmware version 20240318.git3b128b60-0ubuntu2.14 from -proposed [1]. Otherwise, please install the linux-firmware version 20250317.git1d4c88ee-0ubuntu1.3 from -proposed[1].

- Test instructions:
1. Boot the system using the Noble or Plucky generic kernel
2. Since this bug was intended to be fixed only in the Noble 6.14-OEM kernel, it is expected to still reproduce on the Noble and Plucky generic kernels. Please
test all other functionalities to verify whether there are any regressions.


[Where problems could occur]
We updated the firmware to the latest version, while the Linux AMDGPU driver remains behind the mainline. As a consequence, a mismatch might occur between the Linux AMDGPU driver and the firmware.


[1] See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

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