[PATCH/RFC,0/1] arm64: dts: renesas: white-hawk: Add mini-DP output support

Message

Geert Uytterhoeven Oct. 18, 2024, 9:32 a.m. UTC

Hi all,

As I had to test Tomi's WIP patches to add mini-DP output support to
Gray Hawk Single, I moved my (old and new) DisplayPort gear to my board
farm, and thought this was a good opportunity to test mini-DP output on
White Hawk as a baseline (CN5), and add support for the second mini-DP
output on the White Hawk BreakOut board (CN15).

For testing, I used the following hardware:
  (A) BenQ BL2420PT desktop display (2560x1440),
  (B) Joy-It Joy-View 15 portable display (1920x1080),
  (C) Lindy DisplayPort to 2 Port HDMI MST Hub,
  (D) Passive mini-DP to HDMI cable,
  (E) LogiLink Mini DisplayPort to VGA Converter.

(A)-(C) are known to work with my Intel desktop.
(D)-(E) are known to work with an old Dell XPS13.

Software-wise, I used the frame buffer text console, "modetest -M
rcar-du -s 86:1920x1080@XR24" or "modetest -M rcar-du -s
86:2560x1440@XR24", and fbtest.

White Hawk CN5
--------------

  0. General:
      - Hotplug detect does not work, switching display needs a reboot,
      - fbtest test002 crashes with SEGV in 2560x1440.

  1. Mini-DP to (A) DP:
       - 2560x1440 works but flickers (flickering shifts image
	 horizontally; perhaps a cable issue, as 2 below does work?)
       - 1920x1080 is stable

  2. Mini-DP to (C) to (A) HDMI:
       - 2560x1440 OK
       - 1920x1080 OK

  3. Mini-DP to (C) to (B) mini-HDMI:
       - 1920x1080 OK

  4. Mini-DP to (C) to (A) HDMI + (B) mini-HDMI:
       - 1920x1080 mirrored OK

  5. Mini-DP to (E) to (A) HDMI:
       - SN65DSI86 behaves as if no cable is connected.
         Expected, as TI SN65DSI86 does not support Dual-Mode/DP++.

  6. Mini-DP to (D) to (A) VGA:
       - Detected 1920x1080, black screen / no signal.
         Perhaps this adapter relies on DP++, too?


White Hawk CN15
---------------

Does not work:
  - Display resolution is detected correctly (1920x1080 or 2560x1440),
  - Black screen, displays say no signal detected,
  - "modetest -M rcar-du -s 88:1920x1080@XR24" triggers:

	rcar-mipi-dsi fed90000.dsi-encoder: Failed to disable video transmission
	vsp1 fea20000.vsp: Underrun occurred at WPF0 (total underruns 2)

    Note that fea20000.vsp is vspd0, not vspd1. I do have a few similar
    messages for fea28000.vsp in my logs, so this may be a red herring.

Thanks for your comments!

Geert Uytterhoeven (1):
  arm64: dts: renesas: white-hawk: Add mini-DP output support

 .../boot/dts/renesas/r8a779g0-white-hawk.dts  | 90 +++++++++++++++++++
 1 file changed, 90 insertions(+)