** Description changed:
[Impact]
The 4k monitor on the dock is blank when connected to the device.
[Fix]
- Intel provides a patch to fix this issue which disable PSR for the monitors
on MST
+ Intel provides a patch series to address this issue. The patches include
+ fixes for Display Stream Compression (DSC) and Panel Self Refresh (PSR).
+ One of the key changes refines a workaround for a PSR underrun issue,
+ ensuring it is only applied under the correct conditions to prevent
+ display problems on MST setups.
https://patchwork.freedesktop.org/patch/686338/
c390bf07961b drm/i915/dp: Fix panel replay when DSC is enabled
470b84af457e drm/i915/dp_mst: Recompute all MST link CRTCs if DSC gets
enabled on the link
7c027070e98d drm/i915/dp_mst: Track DSC enabled status on the MST link
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
c88e70dc8bfc drm/i915/dsc: Add helper to enable the DSC configuration for a
CRTC
-
[Test]
1. Boot to OS, connect dell dock
2. Connect 4k monitor to dock, it should always work.
[Where problems could occur]
- It disables the PSR for the monitors connected on MST, it may consume more
power.
+ This series of patches touches advanced features in the Intel graphics
+ driver, including Display Stream Compression (DSC), Panel Self Refresh (PSR),
+ and Forward Error Correction (FEC), especially for DisplayPort Multi-Stream
+ Transport (MST). Due to the complexity of these features, regressions
+ could manifest in the following ways:
+
+ - Flickering, link training failures (resulting in a blank screen), or other
+ visual corruption. These issues might occur with specific monitors or docks,
+ especially when using high resolutions or refresh rates.
+
+ - The disabling of PSR for monitors on an MST link is a key part of the fix,
+ which will lead to increased power consumption in those configurations.
+
+ - While aiming to fix a specific problem with a Dell dock, the changes could
+ inadvertently affect other hardware configurations that were previously
+ working correctly, leading to regressions on different docks or monitors.
** Changed in: linux (Ubuntu Noble)
Status: New => Won't Fix
** Changed in: linux (Ubuntu Questing)
Status: New => In Progress
** Changed in: linux (Ubuntu Questing)
Assignee: (unassigned) => AceLan Kao (acelankao)
** Changed in: linux (Ubuntu Resolute)
Status: New => In Progress
** Changed in: linux (Ubuntu Resolute)
Assignee: (unassigned) => AceLan Kao (acelankao)
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https://bugs.launchpad.net/bugs/2131066
Title:
No output on external monitor when connecting to dell dock
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