USB-C port with Linux


#1

I have a Rock960 model A running Ubuntu 16 with the 4.4.103 Linux kernel (I downloaded the image from the 96boards website).

I’m trying to get video output over the USB-C port. Does this configuration support DisplayPort Alternate Mode? I’m not seeing any video output when I try a USB Type-C to DisplayPort Cable. I know the cable and monitor are good (verified with a laptop). Perhaps the 4.4 kernel is too old for DisplayPort Alternate Mode support? I see the patchset was merged to the kernel in June 2018 (so I’m guessing it is in 4.19):
http://lkml.iu.edu/hypermail/linux/kernel/1806.3/03118.html

Additionally, I tried a USB-C device that has Ethernet, HDMI out, VGA out, and a USB 3.0 type A port (Cable Matters 201014). I can’t get this device to work with the Rock960. The Ethernet adapter shows up on another PC as “0b95:1790 ASIX Electronics Corp. AX88179 Gigabit Ethernet”. It seems like the default Rock960 kernel config has "CONFIG_USB_NET_AX88179_178A"set so I should have this driver. Is there something I need to do to force the Rock960 USB-C port into host mode?


#2

type c to HDMI/VAG adapter is supported, type C to type C display is not working yet. You need to update your kernel. If you know how to build the kernel, you can build the latest kernel and replace it. If you don’t want to bother, you can download the newer 18.04 image, we provide update-to-date kernel via repository for ubuntu 18.04.

https://dl.vamrs.com/products/rock960/images/ubuntu/rock960ab-ubuntu-bionic-minimal-arm64-20181218_2036-gpt.img.gz

and then

apt-get install linux-4.4-lastest

#3

Hi, I am also trying to get video output on the Rock96ab using a USB-C to HDMI cable. Currently I have flashed the latest Ubuntu 18.04 image from the downloads page. This came with the 4.4.154-59 Linux Kernel.

Using the command:

apt-get install linux-4.4-lastest

I am able to install the lates kernel on the Rock960ab
linux-4.4.154-73...

However when I reboot the device, uname -a still lists the 4.4.154-59 kernel. Is the latest kernel installed using linux-4.4-lastest necessary to get video output using a USB-C to HDMI cable? If I have to install the latest kernel, how do I get the Rock960 to boot using another kernel? I have tested that the cable works on my desktop running Ubuntu.


#4

Hi, @OscarD

You can mount /dev/mmcblk1p4 to /boot and edit /boot/extlinux/extlinux.conf, make sure the first one is linux-4.4.154-73. By default the newest should be on the top.