[Kernel/FB] ScreenPad display static on FB initialization

[Qonfused]

Follow up to shiecldk/ASUS-ZenBook-Pro-Duo-15-OLED-UX582-Hackintosh#2 investigating scrambled screenpad plus display-out.

IMG_0838-H264_Proxy_half_size.mov

Current tasks:

• Display output
• Pre-OS (OpenCore verbose)
  • GOP (UEFI feature)
• iGPU Framebuffer
  • Proper RGB screenspace
  • QE/CI acceleration
• Display metadata (EDID)
  • Device Name (Cosmetic)
  • Device and Vendor IDs
  • Valid resolution data
    • Native resolution
    • Default resolution
    • Scaled resolutions
  • Valid clock/timings data
  • Physical size info (Cosmetic)
    • Panel dimensions
    • Correct default ppmm
• PCH Sideband signals
  • Display Hotplug
  • Panel power and backlight
  • GMBUS I2C GPIO

[Qonfused]

Found a few item details from https://en.accessoires-asus.com/ regarding the Screenpad Plus:

Item	Image
Asus Screen module blue touch screenpad FHD 12 SKU: MODULESCREENPADUX481BLUEFHD P/N: 90NB0P61-R20010 EDP Cable reference: 1422-03ER0AS
(For main display) Asus Screen cable EDP for UX481FLY SKU: EDPCBLUX481 P/N: 14005-03210100 EDP Cable reference: 1422-03EK0AS
Asus Touch controller card for UX481FLY SKU: TOUCHCONTBDUX481 P/N: 90NB0P60-R10020 Model: 60NB0P60-TP1020

^ Both the screenpad plus assembly and actual primary display cable have an 'EDP cable reference' id, which appear only to deviate by the length of the cable. There however appears to not be any individual catalog item for the screenpad plus's EDP cable (probably only included in the whole top-case assembly linked above).

This also verifies the connector type from the datasheet @UsedDiscord provided, analyzed in #1 (comment) w/ the device schematic however pointing out a DP interface:

I noticed that the screenpad plus is designated as DP (also listed as DDI1) in the device's schematic w/ a different layout than eDP, though it matches what was shown in the datasheet you linked as the physical connector:

On the left is the LCD connector and on the right looks to be for the touchscreen digitizer:

[Qonfused]

I've also noted in #2 (comment) that an entry for the EDID data for the screenpad plus display exists in the linux-hw repository:

I also found the display under the linux hw EDID repo: https://raw.githubusercontent.com/linuxhw/EDID/master/DigitalDisplay.md

MFG	Model	Name	Res	Inch	Made	ID
BOE	BOE087F	HF NV126B5M-N41	1920 x 515	12.6	2019	46E74341751E

edid-decode (hex):

00 ff ff ff ff ff ff 00 09 e5 7f 08 00 00 00 00
01 1d 01 04 a5 1f 08 78 02 d2 2d 93 51 57 8d 28
18 4e 52 00 00 00 01 01 01 01 01 01 01 01 01 01
01 01 01 01 01 01 94 1b 80 a0 70 03 32 20 30 20
55 00 35 53 10 00 00 1a 12 16 80 a0 70 03 32 20
30 20 55 00 35 53 10 00 00 1a 00 00 00 fe 00 42
4f 45 20 48 46 0a 20 20 20 20 20 20 00 00 00 fe
00 4e 56 31 32 36 42 35 4d 2d 4e 34 31 0a 00 ed

#2 already confirms the validity of the EDID data present from the screenpad plus display. This can be further studied in Linux as to whether or not the display is connected to the iGPU through an eDP or a DP interface.

(e.g. https://linux-hardware.org/?probe=d680085d25):

EDID output

edid-decode "/sys/class/drm/card0-DP-1/edid":

EDID (hex):
00ffffffffffff0009e57f0800000000
011d0104a51f087802d22d9351578d28
184e5200000001010101010101010101
010101010101941b80a0700332203020
550035531000001a121680a070033220
3020550035531000001a000000fe0042
4f452048460a202020202020000000fe
004e5631323642354d2d4e34310a00ed

Extracted contents:
header:          00 ff ff ff ff ff ff 00
serial number:   ...
version:         01 04
basic params:    a5 1f 08 78 02
chroma info:     d2 2d 93 51 57 8d 28 18 4e 52
established:     00 00 00
standard:        01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01
descriptor 1:    94 1b 80 a0 70 03 32 20 30 20 55 00 35 53 10 00 00 1a
descriptor 2:    12 16 80 a0 70 03 32 20 30 20 55 00 35 53 10 00 00 1a
descriptor 3:    00 00 00 fe 00 42 4f 45 20 48 46 0a 20 20 20 20 20 20
descriptor 4:    00 00 00 fe 00 4e 56 31 32 36 42 35 4d 2d 4e 34 31 0a
extensions:      00
checksum:        ed

EDID version: 1.4
Manufacturer: BOE Model 87f Serial Number ...
Made in week 1 of 2019
Digital display
8 bits per primary color channel
DisplayPort interface
Maximum image size: 31 cm x 8 cm
Gamma: 2.20
Supported color formats: RGB 4:4:4
First detailed timing includes the native pixel format and preferred refresh rate
Display x,y Chromaticity:
  Red:   0.5771, 0.3173
  Green: 0.3398, 0.5527
  Blue:  0.1562, 0.0957
  White: 0.3076, 0.3212
Established timings supported:
Standard timings supported:
Detailed mode: Clock 70.600 MHz, 309 mm x 83 mm
               1920 1968 2000 2080 hborder 0
                515  520  525  565 vborder 0
               +hsync -vsync 
               VertFreq: 60 Hz, HorFreq: 33942 Hz
Detailed mode: Clock 56.500 MHz, 309 mm x 83 mm
               1920 1968 2000 2080 hborder 0
                515  520  525  565 vborder 0
               +hsync -vsync 
               VertFreq: 48 Hz, HorFreq: 27163 Hz
ASCII string: BOE HF
ASCII string: NV126B5M-N41
Checksum: 0xed (valid)
EDID block does NOT conform to EDID 1.4!
	Missing name descriptor
	Missing monitor ranges
...

gpu-manager.log output

...
Vendor/Device Id: 8086:9b41
BusID "PCI:0@0:2:0"
Is boot vga? yes
Vendor/Device Id: 10de:1d52
BusID "PCI:2@0:0:0"
can't open /sys/bus/pci/devices/0000:02:00.0/boot_vga
Is boot vga? no
...
Found "/dev/dri/card0", driven by "i915"
output 0:
	card0-eDP-1
output 1:
	card0-DP-1
Number of connected outputs for /dev/dri/card0: 2
...

xorg.log output

...
[     9.435] (II) modeset(0): EDID for output DP-1
[     9.435] (II) modeset(0): Manufacturer: BOE  Model: 87f  Serial#: ...
[     9.435] (II) modeset(0): Year: 2019  Week: 1
[     9.435] (II) modeset(0): EDID Version: 1.4
[     9.435] (II) modeset(0): Digital Display Input
[     9.435] (II) modeset(0): 8 bits per channel
[     9.435] (II) modeset(0): Digital interface is DisplayPort
[     9.435] (II) modeset(0): Max Image Size [cm]: horiz.: 31  vert.: 8
[     9.435] (II) modeset(0): Gamma: 2.20
[     9.435] (II) modeset(0): No DPMS capabilities specified
[     9.435] (II) modeset(0): Supported color encodings: RGB 4:4:4 
[     9.435] (II) modeset(0): First detailed timing is preferred mode
[     9.435] (II) modeset(0): Preferred mode is native pixel format and refresh rate
[     9.435] (II) modeset(0): redX: 0.577 redY: 0.317   greenX: 0.340 greenY: 0.553
[     9.435] (II) modeset(0): blueX: 0.156 blueY: 0.096   whiteX: 0.308 whiteY: 0.321
[     9.435] (II) modeset(0): Manufacturer's mask: 0
[     9.435] (II) modeset(0): Supported detailed timing:
[     9.435] (II) modeset(0): clock: 70.6 MHz   Image Size:  309 x 83 mm
[     9.435] (II) modeset(0): h_active: 1920  h_sync: 1968  h_sync_end 2000 h_blank_end 2080 h_border: 0
[     9.435] (II) modeset(0): v_active: 515  v_sync: 520  v_sync_end 525 v_blanking: 565 v_border: 0
[     9.435] (II) modeset(0): Supported detailed timing:
[     9.435] (II) modeset(0): clock: 56.5 MHz   Image Size:  309 x 83 mm
[     9.435] (II) modeset(0): h_active: 1920  h_sync: 1968  h_sync_end 2000 h_blank_end 2080 h_border: 0
[     9.435] (II) modeset(0): v_active: 515  v_sync: 520  v_sync_end 525 v_blanking: 565 v_border: 0
[     9.435] (II) modeset(0):  BOE HF
[     9.435] (II) modeset(0):  NV126B5M-N41
[     9.435] (II) modeset(0): EDID (in hex):
[     9.435] (II) modeset(0): 	00ffffffffffff0009e57f0800000000
[     9.435] (II) modeset(0): 	011d0104a51f087802d22d9351578d28
[     9.435] (II) modeset(0): 	184e5200000001010101010101010101
[     9.435] (II) modeset(0): 	010101010101941b80a0700332203020
[     9.435] (II) modeset(0): 	550035531000001a121680a070033220
[     9.435] (II) modeset(0): 	3020550035531000001a000000fe0042
[     9.436] (II) modeset(0): 	4f452048460a202020202020000000fe
[     9.436] (II) modeset(0): 	004e5631323642354d2d4e34310a00ed
[     9.436] (WW) modeset(0): Output DP-1: Strange aspect ratio (309/83), consider adding a quirk
[     9.436] (WW) modeset(0): Output DP-1: Strange aspect ratio (309/83), consider adding a quirk
[     9.436] (II) modeset(0): Printing probed modes for output DP-1
[     9.436] (II) modeset(0): Modeline "1920x515"x60.1   70.60  1920 1968 2000 2080  515 520 525 565 +hsync -vsync (33.9 kHz eP)
[     9.436] (II) modeset(0): Modeline "1920x515"x48.1   56.50  1920 1968 2000 2080  515 520 525 565 +hsync -vsync (27.2 kHz e)
[     9.444] (II) modeset(0): EDID for output HDMI-1
[     9.444] (II) modeset(0): Output eDP-1 connected
[     9.444] (II) modeset(0): Output DP-1 connected
[     9.444] (II) modeset(0): Output HDMI-1 disconnected
...

[Qonfused]

I do wonder, having tried patching the connector type as DisplayPort in #1 how I'd handle a passive eDP -> DP adapter with WEG patching.

As an example, a validation methodology paper from Intel covered the 'Hardware and Software Uniqueness' (pg. 12) of an eDP to DP cable. They state that since the standards are very similar, a passive adapter can be used without any level shifting (i.e. no active adapter is needed). From the pin layout of the adapter, it looks like you can just forgo eDP-specific capability to operate the display under a normal DisplayPort interface.

The DisplayPort interface shown in #4 (comment) also appears to have an identical layout for its control signals, though it terminates at a 30 pin DisplayPort connector vs a 20 pin eDP connector:

[Qonfused]

It's the same case for the pro-duo as well, which has an eDP connector on the datasheet for the second display, but is connected via DP to the iGPU.