Zhang Yuming

Hello everyone, I have a screen of 1280x800 resolution. while connecting the screen to my rockpi-4b, the resolution is set to 1024x768, and there is no 1280x800 option in the display setting panel. after learning from Internet for days, I think the root is that my screen doesn't have a correct EDID information. so I made some changes to let the kernel ignores the screen's edid information and use specified edid file. The resolution is successfully set to 1280x800, the only problem is that the screen display is shaking, as the attached video shows. The edid file's timing settings are shown as below: I tried to change the settings but it doesn't work. It would be greatly appreciated if somebody can share with me the correct edid file of 1280x800 resolution. Thanks, Yuming normal video.mp4

I found the solution is to disable NetworkManager and Networking, enable the dhcpcd; by this way the ethernet works for me. sudo systemctl stop NetworkManager sudo systemctl disable NetworkManager sudo systemctl stop networking sudo systemctl disable networking sudo apt-get install dhcpcd5 the wireless network is disabled by this way, but can be started by wpa_supplicant, it's another topic.

not exactly, both the PC and the SBC acts as dhcp client. actually there may be two connection cases : one is that the PC and the SBC are connected to a router which has a DHCP server; the other is the PC and the SBC are connected directly.

Hello everyone, I'm using SBC Rockpi4b running the Armbian system. I encountered a problem when using the Ethernet port. I connected the SBC to my laptop via an ethernet cable directly, just like what I did with the RaspberryPi. while playing with RaspberryPi (Raspbian OS) I can get the ethernet connected, the ip address is set to 168.254.xxx.xxx, i.e., private address. then I can successfully ping the RaspberryPi's ip address in my PC. while playing with the SBC (Armbian OS), the network manager seems to keep waiting a DHCP server repeatedly; and after a while (around 40 seconds) it pops up saying the ethernet disconnected; the only way I can make it connected is to set static ip addresses, but it's not the proper solution. After googling for days I realized that the two OS (Raspbian vs Armbian) run different programs for the DHCP. Raspbian apply dhcpcd, Armbian apply NetworkManager. so the first idea came to my mind was using the dhcpcd in Armbian. I have learnt that the NetworkManager can specify to use the dhcpcd as dhcp client. I followed some tutorials: 1. installing dhcpcd (sudo apt-get install dhcpcd5); 2. modifying the /etc/NetworkManager/NetworkManager.conf to add: [main] dhcp=dhcpcd it seems work at the beginning, I can see a 169.254.xxx.xxx ip address in the "ifconfig" output, but after a while it was destroyed. I checked the two services' status: pi@192.168.0.108:~$ sudo systemctl status dhcpcd ● dhcpcd.service - DHCP Client Daemon Loaded: loaded (/lib/systemd/system/dhcpcd.service; enabled; vendor preset: enabled) Active: active (running) since Mon 2022-07-11 14:32:17 CST; 6min ago Docs: man:dhcpcd(8) Process: 861 ExecStart=/usr/sbin/dhcpcd (code=exited, status=0/SUCCESS) Main PID: 1128 (dhcpcd) Tasks: 1 (limit: 4461) Memory: 968.0K CGroup: /system.slice/dhcpcd.service └─1128 /usr/sbin/dhcpcd Jul 11 14:33:25 rockpi-4b dhcpcd[1128]: eth0: adding address fe80::3eb:def9:d81e:17aa Jul 11 14:33:25 rockpi-4b dhcpcd[1128]: ipv6_addaddr1: Permission denied Jul 11 14:33:26 rockpi-4b dhcpcd[1128]: eth0: soliciting a DHCP lease Jul 11 14:33:26 rockpi-4b dhcpcd[1128]: eth0: soliciting an IPv6 router Jul 11 14:33:31 rockpi-4b dhcpcd[1128]: eth0: probing for an IPv4LL address Jul 11 14:33:35 rockpi-4b dhcpcd[1128]: eth0: using IPv4LL address 169.254.39.239 Jul 11 14:33:35 rockpi-4b dhcpcd[1128]: eth0: adding route to 169.254.0.0/16 Jul 11 14:33:51 rockpi-4b dhcpcd[1128]: eth0: deleted route to 169.254.0.0/16 Jul 11 14:33:51 rockpi-4b dhcpcd[1128]: eth0: adding route to 169.254.0.0/16 Jul 11 14:33:51 rockpi-4b dhcpcd[1128]: if_route (ADD): Invalid argument pi@192.168.0.108:~$ sudo systemctl status NetworkManager ● NetworkManager.service - Network Manager Loaded: loaded (/lib/systemd/system/NetworkManager.service; enabled; vendor preset: enabled) Active: active (running) since Mon 2022-07-11 14:32:17 CST; 6min ago Docs: man:NetworkManager(8) Main PID: 860 (NetworkManager) Tasks: 3 (limit: 4461) Memory: 13.8M CGroup: /system.slice/NetworkManager.service └─860 /usr/sbin/NetworkManager --no-daemon Jul 11 14:34:36 rockpi-4b NetworkManager[860]: <info> [1657521276.7314] device (eth0): state change: config -> ip-config (reason 'none', sys-iface-state: 'managed') Jul 11 14:34:36 rockpi-4b NetworkManager[860]: <info> [1657521276.7344] dhcp4 (eth0): activation: beginning transaction (timeout in 45 seconds) Jul 11 14:35:21 rockpi-4b NetworkManager[860]: <warn> [1657521321.6769] dhcp4 (eth0): request timed out Jul 11 14:35:21 rockpi-4b NetworkManager[860]: <info> [1657521321.6771] dhcp4 (eth0): state changed unknown -> timeout Jul 11 14:35:21 rockpi-4b NetworkManager[860]: <info> [1657521321.6773] device (eth0): state change: ip-config -> failed (reason 'ip-config-unavailable', sys-iface-state: 'ma> Jul 11 14:35:21 rockpi-4b NetworkManager[860]: <warn> [1657521321.6828] device (eth0): Activation: failed for connection 'Wired connection 1' Jul 11 14:35:21 rockpi-4b NetworkManager[860]: <info> [1657521321.6842] device (eth0): state change: failed -> disconnected (reason 'none', sys-iface-state: 'managed') Jul 11 14:35:21 rockpi-4b NetworkManager[860]: <info> [1657521321.7049] dhcp4 (eth0): canceled DHCP transaction Jul 11 14:35:21 rockpi-4b NetworkManager[860]: <info> [1657521321.7051] dhcp4 (eth0): state changed timeout -> done Jul 11 14:35:21 rockpi-4b NetworkManager[860]: <info> [1657521321.7177] manager: startup complete It's my first post here, it will be greatly appreciated if anyone could tell me how to make the NetworkManager stop reinitializing the ethernet connection and assign a private ip address (169.254.xxx.xxx) instead? Regards, Yuming