[SRU][Q][PATCH 0/9] No output on external monitor when connecting to dell dock

[AceLan Kao]

From: "Chia-Lin Kao (AceLan)" <acelan.kao at canonical.com>

BugLink: https://bugs.launchpad.net/bugs/2131066

[Impact]
The 4k monitor on the dock is blank when connected to the device.

[Fix]
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]
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.


Gustavo Sousa (1):
  drm/i915/display: Remove unused declarations of intel_io_*

Imre Deak (7):
  drm/i915/dsc: Add helper to enable the DSC configuration for a CRTC
  drm/i915/dp: Ensure the FEC state stays disabled for UHBR links
  drm/i915/dp: Export helper to determine if FEC on non-UHBR links is
    required
  drm/i915/dp_mst: Reuse the DP-SST helper function to compute FEC
    config
  drm/i915/dp_mst: Track DSC enabled status on the MST link
  drm/i915/dp_mst: Recompute all MST link CRTCs if DSC gets enabled on
    the link
  drm/i915/dp: Fix panel replay when DSC is enabled

Jouni Högander (1):
  drm/i915/psr: Underrun on idle PSR wa only when pkgc latency > delayed
    vblank

 drivers/gpu/drm/i915/display/icl_dsi.c        |   2 +-
 drivers/gpu/drm/i915/display/intel_display.c  |   2 +-
 .../drm/i915/display/intel_display_types.h    |  15 ++-
 drivers/gpu/drm/i915/display/intel_dp.c       |  34 ++++--
 drivers/gpu/drm/i915/display/intel_dp.h       |   2 +
 drivers/gpu/drm/i915/display/intel_dp_mst.c   |  31 ++---
 drivers/gpu/drm/i915/display/intel_link_bw.c  |  17 +--
 drivers/gpu/drm/i915/display/intel_link_bw.h  |   2 +-
 drivers/gpu/drm/i915/display/intel_psr.c      | 109 ++++++++++++++++--
 drivers/gpu/drm/i915/display/intel_vdsc.c     |  16 +++
 drivers/gpu/drm/i915/display/intel_vdsc.h     |   2 +
 drivers/gpu/drm/i915/display/skl_watermark.c  |   5 +
 12 files changed, 187 insertions(+), 50 deletions(-)

-- 
2.43.0