[Bug 2130773] Re: External monitors on Dell dock are blank or can't be detected

** Description changed:

[Impact]
External monitors on Dell dock are blank or can't be detected.

[Fix]
Intel submit a patch to fix this issue
https://lore.kernel.org/all/20251028113536.602352-1-imre.deak@intel.com/
This patch is included in linux-next
06a691f0e7d0 drm/i915/dp_mst: Fix check for FEC support for an uncompressed stream
-
- To resolve the conflicts, cherry picked 3 more commits from linux-next
- b762ae48293e drm/i915/dp_mst: Reuse the DP-SST helper function to compute FEC config
- cb6c8f1f6f46 drm/i915/dp: Export helper to determine if FEC on non-UHBR links is required
- 69df31263bca drm/i915/dp: Ensure the FEC state stays disabled for UHBR links

[Test]
1. Connect three external monitor to dock WD22TB4
2. Connect dock to system
3. Do unplug and plug serval times, the monitors should be recognized and work well.

[Where problems could occur]
Users with MST monitor setups (especially MST docks with multiple monitors) may
experience display initialization failures or blank screens when one monitor
doesn't support FEC but another monitor on the same link uses DSC compression.
Additionally, users could encounter inconsistent display behavior where monitors
work or fail depending on the order they're detected or what link rates are
negotiated.

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https://bugs.launchpad.net/bugs/2130773

Title:
External monitors on Dell dock are blank or can't be detected

Status in HWE Next:
New
Status in linux package in Ubuntu:
Invalid
Status in linux-oem-6.14 package in Ubuntu:
Invalid
Status in linux-oem-6.17 package in Ubuntu:
Invalid
Status in linux source package in Noble:
Won't Fix
Status in linux-oem-6.14 source package in Noble:
In Progress
Status in linux-oem-6.17 source package in Noble:
In Progress
Status in linux source package in Plucky:
In Progress
Status in linux-oem-6.14 source package in Plucky:
Invalid
Status in linux-oem-6.17 source package in Plucky:
Invalid
Status in linux source package in Questing:
In Progress
Status in linux-oem-6.14 source package in Questing:
Invalid
Status in linux-oem-6.17 source package in Questing:
Invalid

Bug description:
[Impact]
External monitors on Dell dock are blank or can't be detected.

[Fix]
Intel submit a patch to fix this issue
https://lore.kernel.org/all/20251028113536.602352-1-imre.deak@intel.com/
This patch is included in linux-next
06a691f0e7d0 drm/i915/dp_mst: Fix check for FEC support for an uncompressed stream

[Test]
1. Connect three external monitor to dock WD22TB4
2. Connect dock to system
3. Do unplug and plug serval times, the monitors should be recognized and work well.

[Where problems could occur]
Users with MST monitor setups (especially MST docks with multiple monitors) may
experience display initialization failures or blank screens when one monitor
doesn't support FEC but another monitor on the same link uses DSC compression.
Additionally, users could encounter inconsistent display behavior where monitors
work or fail depending on the order they're detected or what link rates are
negotiated.

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