[SRU] [H/U/OEM-5.10] [PATCH 0/1] Fix no picture from HDMI when it's plugged after boot

[Kai-Heng Feng]

BugLink: https://bugs.launchpad.net/bugs/1924238

[Impact]
On Intel CML desktop, there's no HDMI output when the cable is not
connected pre-boot.

[Fix]
Properly handle lane polarity so the driver can write different values
to the register to enable the port.

[Test]
1. Boot with DP display.
2. Connect HDMI under GNOME desktop.
3. No picture on HDMI monitor.
With the fix applied, the issue is resolved.

[Where problems could occur]
If the BIOS VBT table is not correct, which did happen in the pase, this
fix may break those ports.

Uma Shankar (1):
  drm/i915/display: Handle lane polarity for DDI port

 drivers/gpu/drm/i915/display/intel_bios.c | 17 +++++++++++++++++
 drivers/gpu/drm/i915/display/intel_bios.h |  2 ++
 drivers/gpu/drm/i915/display/intel_ddi.c  |  3 +++
 3 files changed, 22 insertions(+)

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2.30.2