Librem 5 does not work with LG ‎34UC99-W (anymore)

epinez · August 13, 2023, 3:21pm

Hey guys! After getting my Librem 5 I tried to connect it to my Display via its integrated USB-C. It worked at first but I had some kind of small pixel artifacts all over the screen. I decided to not bother and wait for future upgrades which could maybe solve this problem.

Fast forward a.k.a. a few months later…

Today I tried it again and I didn’t get any signal on the display at all. Black screen. Turning the USB-C cable the other way around did not help. After reconnecting a few times it once showed the connected to dock icon on the Librem 5 but no signal again. This was with the USB cable which came with the monitor. The Librem 5 included cable also didn’t work. Connected devices on the hub ports like mouse and keyboard worked without any problem and the Librem 5 also charges. Unplugging these devices shows no difference…

Is there anything I could do?

Monitor:

LG 34UC99-W
3440*1440
Data sheet mentions the following for USB-C port:

• PD (Power Delivery), DP alternate Mode (DP over USB-C) and USB Data are
supported via USB-C Port.
• Features may not work properly depending on the connected device’s specifications
and the environment.
• USB-C port is not for the Monitor Power source but for a PC power source.
Connect adapter to supply power to the Monitor

Help is very appreciated! Thanks in advance.

irvinewade · August 15, 2023, 4:26am

What does lsusb say?

Anything in the Librem 5’s system journal?

epinez · August 15, 2023, 6:24am

Thanks for your answer! I’ll check that in a few days when I’m back home

epinez · September 1, 2023, 10:46am

Hey @irvinewade

Please see the attached output:

purism@librem:~$ lsusb

Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 0424:4041 Microchip Technology, Inc. (formerly SMSC) Hub and media card controller
Bus 001 Device 002: ID 0424:2640 Microchip Technology, Inc. (formerly SMSC) USB 2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

After attaching the monitor + hubs etc.

purism@librem:~$ lsusb

Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 0424:4041 Microchip Technology, Inc. (formerly SMSC) Hub and media card controller
Bus 001 Device 002: ID 0424:2640 Microchip Technology, Inc. (formerly SMSC) USB 2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 004: <redacted usb ethernet adapter>
Bus 004 Device 003: ID 0bda:0411 Realtek Semiconductor Corp. Hub
Bus 004 Device 002: ID 0451:8140 Texas Instruments, Inc. TUSB8041 4-Port Hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 005: <redacted camera>
Bus 003 Device 007: <redacted keyboard>
Bus 003 Device 006: <redacted mouse>
Bus 003 Device 004: ID 0bda:5411 Realtek Semiconductor Corp. RTS5411 Hub
Bus 003 Device 003: ID 0451:3421 Texas Instruments, Inc. Texas Instruments USB Billboard Device
Bus 003 Device 002: ID 0451:8142 Texas Instruments, Inc. TUSB8041 4-Port Hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

I’d think the monitor could be the Texas Instruments USB Billboard Device ?

Below are snippets from journalctl -r --since "5min ago" (I tried to filter out things which seem most important to not have to redact such many information. I could later give the whole log if necessary):

purism@librem:~$ journalctl -r --since "5min ago"
-- Journal begins at Sun 2022-08-07 15:25:10 CEST, ends at Fri 2023-09-01 11:57:58 CEST. --

Sep 01 11:57:58 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.
Sep 01 11:57:53 librem kernel: cdns-mhdp-imx 32c00000.hdmi: Wait PLL disable Ack failed
Sep 01 11:57:53 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.
Sep 01 11:57:48 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.
Sep 01 11:57:42 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.
Sep 01 11:57:37 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.
Sep 01 11:57:32 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.
Sep 01 11:57:27 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.
Sep 01 11:57:22 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.
Sep 01 11:57:17 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.
Sep 01 11:57:17 librem gsd-color[1175]: unable to get EDID for xrandr-DSI-1: unable to get EDID for output
Sep 01 11:57:17 librem gsd-xsettings[1195]: Failed to get current UI legacy scaling factor
Sep 01 11:57:17 librem gsd-xsettings[1195]: Failed to get current UI legacy scaling factor
Sep 01 11:57:16 librem kernel: edt_ft5x06 2-0038: Unable to fetch data, error: -6
Sep 01 11:57:12 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.
Sep 01 11:57:07 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.
Sep 01 11:57:02 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.
Sep 01 11:56:57 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.
Sep 01 11:56:52 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.
Sep 01 11:56:47 librem kernel: cdns-mhdp-imx 32c00000.hdmi: [drm:cdns_mhdp_reg_read [cdns_mhdp_drmcore]] *ERROR* Failed to read register.


Sep 01 11:56:34 librem kernel: usb 4-1.2: Device is not authorized for usage
Sep 01 11:56:34 librem kernel: usb 4-1.2: Manufacturer: Generic
Sep 01 11:56:34 librem kernel: usb 4-1.2: Product: 4-Port USB 3.0 Hub
Sep 01 11:56:34 librem kernel: usb 4-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
Sep 01 11:56:34 librem kernel: usb 4-1.2: New USB device found, idVendor=0bda, idProduct=0411, bcdDevice= 1.21
Sep 01 11:56:34 librem kernel: usb 3-1.1: authorized to connect
Sep 01 11:56:34 librem kernel: hid-generic 0003:0451:3421.0011: hiddev96,hidraw0: USB HID v1.11 Device [Texas Instruments Inc. Texas Instruments USB Billboard Device] on usb-xhci-hcd.5.auto-1.1/input1
Sep 01 11:56:34 librem usbguard-daemon[765]: uid=0 pid=662 result='SUCCESS' device.system_name='/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb3/3-1/3-1.1' target.new='allow' device.rule='block id 0451:3421 serial "9CFF6429838C1F56" name "Texas Instruments USB Billboard Device" hash "l9YTGwE28tbfJZQNcMrtbzLKHRb5nqFaAHu9D8vW2WU=" parent-hash "C5HatT5EmR/UlfoCNV/psDynke+rLJ+XsqyCrYd2WGM=" via-port "3-1.1" with-interface { 11:00:00 03:00:00 } with-connect-type "unknown"' target.old='block' type='Policy.Device.Update'
Sep 01 11:56:34 librem kernel: usb 4-1.2: new SuperSpeed USB device number 3 using xhci-hcd
Sep 01 11:56:34 librem mtp-probe[6731]: bus: 3, device: 3 was not an MTP device
Sep 01 11:56:34 librem mtp-probe[6731]: checking bus 3, device 3: "/sys/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb3/3-1/3-1.1"
Sep 01 11:56:34 librem usbguard-daemon[765]: uid=0 pid=662 result='SUCCESS' device.rule='block id 0451:3421 serial "9CFF6429838C1F56" name "Texas Instruments USB Billboard Device" hash "l9YTGwE28tbfJZQNcMrtbzLKHRb5nqFaAHu9D8vW2WU=" parent-hash "C5HatT5EmR/UlfoCNV/psDynke+rLJ+XsqyCrYd2WGM=" via-port "3-1.1" with-interface { 11:00:00 03:00:00 } with-connect-type "unknown"' device.system_name='/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb3/3-1/3-1.1' type='Device.Insert'
Sep 01 11:56:34 librem kernel: usb 3-1.1: Device is not authorized for usage
Sep 01 11:56:34 librem kernel: usb 3-1.1: SerialNumber: 9CFF6429838C1F56
Sep 01 11:56:34 librem kernel: usb 3-1.1: Manufacturer: Texas Instruments Inc.
Sep 01 11:56:34 librem kernel: usb 3-1.1: Product: Texas Instruments USB Billboard Device
Sep 01 11:56:34 librem kernel: usb 3-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Sep 01 11:56:34 librem kernel: usb 3-1.1: New USB device found, idVendor=0451, idProduct=3421, bcdDevice= 1.00
Sep 01 11:56:33 librem kernel: usb 3-1.1: new full-speed USB device number 3 using xhci-hcd
Sep 01 11:56:33 librem upowerd[996]: treating change event as add on /sys/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb4/4-1
Sep 01 11:56:33 librem kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
Sep 01 11:56:33 librem kernel: bq25890-charger 3-006a: Upstream supply changed: 1.
Sep 01 11:56:33 librem upowerd[996]: treating change event as add on /sys/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb3/3-1
Sep 01 11:56:33 librem kernel: usb 4-1: authorized to connect
Sep 01 11:56:33 librem kernel: hub 4-1:1.0: 3 ports detected
Sep 01 11:56:33 librem kernel: hub 4-1:1.0: USB hub found
Sep 01 11:56:33 librem usbguard-daemon[765]: Ignoring unknown UEvent action: sysfs_devpath=/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb4/4-1 action=change
Sep 01 11:56:33 librem usbguard-daemon[765]: uid=0 pid=662 result='SUCCESS' device.system_name='/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb4/4-1' target.new='allow' device.rule='block id 0451:8140 serial "" name "" hash "dVCymwEseQzOxQLvV2aMaQqCXF0z5xnHiHD5odaR/TM=" parent-hash "G/QjSJzB6wJUsQhzW88okvkIFDx1hMMGTAEgq65aNxs=" via-port "4-1" with-interface 09:00:00 with-connect-type "unknown"' target.old='block' type='Policy.Device.Update'
Sep 01 11:56:33 librem usbguard-daemon[765]: uid=0 pid=662 result='SUCCESS' device.rule='block id 0451:8140 serial "" name "" hash "dVCymwEseQzOxQLvV2aMaQqCXF0z5xnHiHD5odaR/TM=" parent-hash "G/QjSJzB6wJUsQhzW88okvkIFDx1hMMGTAEgq65aNxs=" via-port "4-1" with-interface 09:00:00 with-connect-type "unknown"' device.system_name='/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb4/4-1' type='Device.Insert'
Sep 01 11:56:33 librem kernel: usb 4-1: Device is not authorized for usage
Sep 01 11:56:33 librem kernel: usb 4-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
Sep 01 11:56:33 librem kernel: usb 4-1: New USB device found, idVendor=0451, idProduct=8140, bcdDevice= 1.00
Sep 01 11:56:33 librem usbguard-daemon[765]: Ignoring unknown UEvent action: sysfs_devpath=/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb3/3-1 action=change
Sep 01 11:56:33 librem usbguard-daemon[765]: uid=0 pid=662 result='SUCCESS' device.system_name='/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb3/3-1' target.new='allow' device.rule='block id 0451:8142 serial "41010879ABD1" name "" hash "C5HatT5EmR/UlfoCNV/psDynke+rLJ+XsqyCrYd2WGM=" parent-hash "U1nFyrkh8NpSDAU6gmicq7SQ13ff+o3bmO/lcp19jvA=" via-port "3-1" with-interface { 09:00:01 09:00:02 } with-connect-type "unknown"' target.old='block' type='Policy.Device.Update'
Sep 01 11:56:33 librem kernel: usb 3-1: authorized to connect
Sep 01 11:56:33 librem kernel: usb 4-1: new SuperSpeed USB device number 2 using xhci-hcd
Sep 01 11:56:33 librem kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
Sep 01 11:56:33 librem kernel: bq25890-charger 3-006a: Upstream supply changed: 1.
Sep 01 11:56:33 librem kernel: hub 3-1:1.0: 3 ports detected
Sep 01 11:56:33 librem kernel: hub 3-1:1.0: USB hub found
Sep 01 11:56:33 librem usbguard-daemon[765]: uid=0 pid=662 result='SUCCESS' device.rule='block id 0451:8142 serial "41010879ABD1" name "" hash "C5HatT5EmR/UlfoCNV/psDynke+rLJ+XsqyCrYd2WGM=" parent-hash "U1nFyrkh8NpSDAU6gmicq7SQ13ff+o3bmO/lcp19jvA=" via-port "3-1" with-interface { 09:00:01 09:00:02 } with-connect-type "unknown"' device.system_name='/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb3/3-1' type='Device.Insert'
Sep 01 11:56:33 librem kernel: usb 3-1: Device is not authorized for usage
Sep 01 11:56:33 librem kernel: usb 3-1: SerialNumber: 41010879ABD1
Sep 01 11:56:33 librem kernel: usb 3-1: New USB device strings: Mfr=0, Product=0, SerialNumber=1
Sep 01 11:56:33 librem kernel: usb 3-1: New USB device found, idVendor=0451, idProduct=8142, bcdDevice= 1.00
Sep 01 11:56:33 librem kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
Sep 01 11:56:33 librem kernel: bq25890-charger 3-006a: Upstream supply changed: 1.
Sep 01 11:56:33 librem kernel: usb 3-1: new high-speed USB device number 2 using xhci-hcd
Sep 01 11:56:32 librem usbguard-daemon[765]: uid=0 pid=662 result='SUCCESS' device.system_name='/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb4' target.new='allow' device.rule='allow id 1d6b:0003 serial "xhci-hcd.5.auto" name "xHCI Host Controller" hash "G/QjSJzB6wJUsQhzW88okvkIFDx1hMMGTAEgq65aNxs=" parent-hash "KXlald6eHhgVzxEC+F9GN7dshRENSCw45OyqsVHzcD8=" via-port "usb4" with-interface 09:00:00 with-connect-type ""' target.old='allow' type='Policy.Device.Update'
Sep 01 11:56:32 librem usbguard-daemon[765]: uid=0 pid=662 result='SUCCESS' device.rule='allow id 1d6b:0003 serial "xhci-hcd.5.auto" name "xHCI Host Controller" hash "G/QjSJzB6wJUsQhzW88okvkIFDx1hMMGTAEgq65aNxs=" parent-hash "KXlald6eHhgVzxEC+F9GN7dshRENSCw45OyqsVHzcD8=" via-port "usb4" with-interface 09:00:00 with-connect-type ""' device.system_name='/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb4' type='Device.Insert'
Sep 01 11:56:32 librem usbguard-daemon[765]: uid=0 pid=662 result='SUCCESS' device.system_name='/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb3' target.new='allow' device.rule='allow id 1d6b:0002 serial "xhci-hcd.5.auto" name "xHCI Host Controller" hash "U1nFyrkh8NpSDAU6gmicq7SQ13ff+o3bmO/lcp19jvA=" parent-hash "KXlald6eHhgVzxEC+F9GN7dshRENSCw45OyqsVHzcD8=" via-port "usb3" with-interface 09:00:00 with-connect-type ""' target.old='allow' type='Policy.Device.Update'
Sep 01 11:56:32 librem usbguard-daemon[765]: uid=0 pid=662 result='SUCCESS' device.rule='allow id 1d6b:0002 serial "xhci-hcd.5.auto" name "xHCI Host Controller" hash "U1nFyrkh8NpSDAU6gmicq7SQ13ff+o3bmO/lcp19jvA=" parent-hash "KXlald6eHhgVzxEC+F9GN7dshRENSCw45OyqsVHzcD8=" via-port "usb3" with-interface 09:00:00 with-connect-type ""' device.system_name='/devices/platform/soc@0/38100000.usb/xhci-hcd.5.auto/usb3' type='Device.Insert'
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Upstream supply changed: 1.
Sep 01 11:56:32 librem kernel: hub 4-0:1.0: 1 port detected
Sep 01 11:56:32 librem kernel: hub 4-0:1.0: USB hub found
Sep 01 11:56:32 librem kernel: usb usb4: SerialNumber: xhci-hcd.5.auto
Sep 01 11:56:32 librem kernel: usb usb4: Manufacturer: Linux 6.3.0-1-librem5 xhci-hcd
Sep 01 11:56:32 librem kernel: usb usb4: Product: xHCI Host Controller
Sep 01 11:56:32 librem kernel: usb usb4: New USB device strings: Mfr=3, Product=2, SerialNumber=1
Sep 01 11:56:32 librem kernel: usb usb4: New USB device found, idVendor=1d6b, idProduct=0003, bcdDevice= 6.03
Sep 01 11:56:32 librem kernel: usb usb4: We don't know the algorithms for LPM for this host, disabling LPM.
Sep 01 11:56:32 librem kernel: hub 3-0:1.0: 1 port detected
Sep 01 11:56:32 librem kernel: hub 3-0:1.0: USB hub found
Sep 01 11:56:32 librem kernel: usb usb3: SerialNumber: xhci-hcd.5.auto
Sep 01 11:56:32 librem kernel: usb usb3: Manufacturer: Linux 6.3.0-1-librem5 xhci-hcd
Sep 01 11:56:32 librem kernel: usb usb3: Product: xHCI Host Controller
Sep 01 11:56:32 librem kernel: usb usb3: New USB device strings: Mfr=3, Product=2, SerialNumber=1
Sep 01 11:56:32 librem kernel: usb usb3: New USB device found, idVendor=1d6b, idProduct=0002, bcdDevice= 6.03
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Upstream supply changed: 1.
Sep 01 11:56:32 librem kernel: xhci-hcd xhci-hcd.5.auto: Host supports USB 3.0 SuperSpeed
Sep 01 11:56:32 librem kernel: xhci-hcd xhci-hcd.5.auto: new USB bus registered, assigned bus number 4
Sep 01 11:56:32 librem kernel: xhci-hcd xhci-hcd.5.auto: xHCI Host Controller
Sep 01 11:56:32 librem kernel: xhci-hcd xhci-hcd.5.auto: irq 207, io mem 0x38100000
Sep 01 11:56:32 librem kernel: xhci-hcd xhci-hcd.5.auto: hcc params 0x0220fe6c hci version 0x110 quirks 0x0000000000010010
Sep 01 11:56:32 librem kernel: xhci-hcd xhci-hcd.5.auto: new USB bus registered, assigned bus number 3
Sep 01 11:56:32 librem kernel: xhci-hcd xhci-hcd.5.auto: xHCI Host Controller
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Upstream supply changed: 1.
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Upstream supply changed: 1.
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Upstream supply changed: 1.
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Upstream supply changed: 1.
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Upstream supply changed: 1.
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
Sep 01 11:56:32 librem kernel: bq25890-charger 3-006a: Upstream supply changed: 1.
Sep 01 11:56:09 librem kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
Sep 01 11:56:09 librem kernel: bq25890-charger 3-006a: Upstream supply changed: 0.
Sep 01 11:56:09 librem kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
Sep 01 11:56:09 librem kernel: bq25890-charger 3-006a: Upstream supply changed: 0.

It seems the *ERROR* Failed to read register. with cdns-mhdp-imx 32c00000.hdmi: points to the problem?

Any help would be apreciated. Or maybe @dos has an idea?

ChriChri · September 1, 2023, 6:15pm

Did you already find this page on the community wiki?

irvinewade · September 1, 2023, 11:55pm

Yes. That’s how a potential monitor shows up (over USB). (So, as far as you got, that’s a good sign.)

Failing to get the EDID info is not ideal - because the system uses that info to understand the parameters of the display (make/model, physical size, pixel clock, valid combinations of resolution and refresh, overscan, …).

I imagine that over USB-C this is all heavily emulated since this is pretend DisplayPort and even more pretend I2C.

On a real display connection (e.g. HDMI) and with the right packages installed you can use
get-edid | parse-edid
to see the kinds of info that can be gleaned.

(I would imagine that, if not already, there will be a non-legacy, standard interface for getting display info over USB-C.)

To use your monitor really needs someone with detailed internals knowledge to sort out where the combination is going wrong. The saving grace that might interest Purism is that this appears to be a regression i.e. went from working but with some display artifacts to not working at all.