Dell U4323QE with KVM - no displays found

[rogerguess]

Dell U4323QE with KVM.

My problem is even with DDC/CI turned ON in the monitor settings, ddcutil is not able to communicate with the monitor.

The end goal is a Raspberry Pi Zero 2 with 4 buttons for fast switching. I have two Macs, a win pc and a jetson orin nano. The Dell software for switching just does not cut it. I have tried from the RPI and from my Jetson running ubuntu. Neither can seem to see the monitor.

output from detect, environment:

roger@orin-nano:~$ sudo ddcutil detect
[sudo] password for roger: 
(i2c_set_addr                  ) set_addr(/dev/i2c-0,I2C_SLAVE,0x50) failed, error = EBUSY
No displays found.
Is DDC/CI enabled in the monitor's on screen display?
Run "ddcutil environment" to check for system configuration problems.
roger@orin-nano:~$ ddcutil environment
The following tests probe the runtime environment using multiple overlapping methods.
*** Basic System Information ***

ddcutil version: 1.2.2

/proc/version:
   Linux version 5.15.148-tegra (buildbrain@mobile-u64-6344-d7000) (aarch64-buildroot-linux-gnu-gcc.br_real (Buildroot 2022.08) 11.3.0, GNU ld (GNU Binutils) 2.38) #1 SMP PREEMPT Thu Dec 12 15:37:09 PST 2024

Architecture:     aarch64
Distributor id:   Ubuntu
Release:          22.04
Found a known architecture

/proc/cmdline:
   root=/dev/mmcblk0p1 rw rootwait rootfstype=ext4 mminit_loglevel=4 console=ttyTCU0,115200 firmware_class.path=/etc/firmware fbcon=map:0 nospectre_bhb video=efifb:off console=tty0 bl_prof_dataptr=2031616@0x271E10000 bl_prof_ro_ptr=65536@0x271E00000 

*** Primary Check 1: Identify video card and driver ***

Obtaining card and driver information from /sys...

*** Primary Check 2: Check that /dev/i2c-* exist and writable ***

Current user: roger (1000)

Checking /dev/i2c-* devices...

Devices /dev/i2c-* must exist and the logged on user must have read/write permission for those devices (or at least those devices associated 
with monitors).

Typically, this access is enabled by:
  - setting the group for /dev/i2c-* to i2c
  - setting group RW permissions for /dev/i2c-*
  - making the current user a member of group i2c

Alternatively, this can be enabled by just giving everyone RW permission
The following tests probe for these conditions.

Checking for /dev/i2c-* devices...
   crw-rw---- 1 root i2c 89,  0 Nov 21  2023 /dev/i2c-0
   crw-rw---- 1 root i2c 89,  1 Nov 21  2023 /dev/i2c-1
   crw-rw---- 1 root i2c 89, 10 Nov 21  2023 /dev/i2c-10
   crw-rw---- 1 root i2c 89, 11 Feb  1 21:16 /dev/i2c-11
   crw-rw---- 1 root i2c 89,  2 Nov 21  2023 /dev/i2c-2
   crw-rw---- 1 root i2c 89,  4 Nov 21  2023 /dev/i2c-4
   crw-rw---- 1 root i2c 89,  5 Nov 21  2023 /dev/i2c-5
   crw-rw---- 1 root i2c 89,  7 Nov 21  2023 /dev/i2c-7
   crw-rw---- 1 root i2c 89,  9 Nov 21  2023 /dev/i2c-9

Current user (roger) has RW access to all /dev/i2c-* devices.

*** Primary Check 3: Check that module i2c_dev is loaded ***

Checking for driver i2c_dev...
   sysfs reports module i2c_dev is NOT loaded.
   Module i2c_dev is built into the kernel

*** Primary Check 4: Driver specific checks ***

Performing driver specific checks...
No driver specific checks apply.

*** Additional probes ***

Examining /sys/bus/i2c/devices...
   /sys/bus/i2c/devices/4-003c/name:  vrs-pseq
   /sys/bus/i2c/devices/i2c-0/name:   3160000.i2c
   /sys/bus/i2c/devices/i2c-1/name:   c240000.i2c
   /sys/bus/i2c/devices/i2c-2/name:   3180000.i2c
   /sys/bus/i2c/devices/i2c-4/name:   Tegra BPMP I2C adapter
   /sys/bus/i2c/devices/i2c-5/name:   31b0000.i2c
   /sys/bus/i2c/devices/i2c-7/name:   c250000.i2c
   /sys/bus/i2c/devices/i2c-9/name:   i2c-2-mux (chan_id 1)
   /sys/bus/i2c/devices/i2c-10/name:  i2c-2-mux (chan_id 0)
   /sys/bus/i2c/devices/10-0010/name: imx219
   /sys/bus/i2c/devices/9-0010/name:  imx219
   /sys/bus/i2c/devices/i2c-11/name:  NVIDIA SOC i2c adapter 0
   /sys/bus/i2c/devices/1-0025/name:  fusb301
   /sys/bus/i2c/devices/1-0040/name:  ina3221
   /sys/bus/i2c/devices/0-0050/name:  24c02
   /sys/bus/i2c/devices/0-0057/name:  24c02

Env_Accumulator:
   architecture:                  aarch64
   distributor_id                 Ubuntu
   Drivers detected:              
   /dev/i2c device numbers:       0 1 2 4 5 7 9 10 11
   sysfs_i2c_devices_exist:       true
   /sys/bus/i2c device numbers:   0 1 2 4 5 7 9 10 11
   dev_i2c_devices_required:      true
   module_i2c_dev_needed:         true
   module_i2c_dev_builtin:        true
   loadable_i2c_dev_exists:       false
   i2c_dev_loaded_or_builtin:     true
   group_i2c_checked:             true
   group_i2c_exists:              true
   dev_i2c_common_group_name:     i2c
   all_dev_i2c_has_group_i2c:     true
   any_dev_i2c_has_group_i2c:     true
   all_dev_i2c_is_group_rw:       true
   any_dev_i2c_is_group_rw:       true
   cur_uname:                     roger
   cur_uid:                       1000
   cur_user_in_group_i2c:         true
   cur_user_any_devi2c_rw:        true
   cur_user_all_devi2c_rw:        true

Configuration suggestions:
   Current user has RW access to all /dev/i2c-N devices.
   Skipping further group and permission checks.

roger@orin-nano:~$ 

[brtwrs]

Some Dell monitors have a wrong EDID header when using Higher Primary resolution. You can switch to a Lower Primary resolution. Somehow the header is now correct.

https://www.dell.com/support/kbdoc/en-us/000182893/dell-u4021qw-monitor-has-abnormal-display-on-chrome-os