Hello,
I have a Type C To HDMI Adapter, which works with my phone, but doesn’t work with Rock 5B.
Neither HDMI nor USB port work.
USB Type-C DP Alt mode doesn't work
try a different adaptor maybe this one is incompatible
What do you power the 5B when you are using the USB C adapter.
it’s just a regular 5V 3A power supply.
I was able to enable USB port on the hub by running the following command:
echo host > /sys/kernel/debug/usb/fc000000.usb/mode
but HDMI port still doesn’t work (probably displayport alt mode isn’t enabled in device tree?).
" DP Alt mode" stands for “DisplayPort Alternate Mode”.
It’s an DisplayPort port signal that comes out of that port, not a HDMI, and your adapter doesn’t have a DP->HDMI converter chip in it (for that price it’s normal).
1 Like
On my side, I observed random issues, sometimes usb-c video working, sometimes not… for now I’m using hdmi cable instead until this is fixed. Hopefully this will be improved with software
This shouldn’t be an issue DP does carry HDMI with it anyways. HDMI to DP is a simple thing of contact conversion.
No, not at all. It requires a chip to do such conversion and that’s why DP/HDMI converters are expensive.
Maybe I am wrong, but there are 3€ ~ 3$ DP to HDMI converters out there on ebay.
Also If you read the article on Wikipedia on DP, you will see that DisplayPort seems to carry an HDMI signal if necessary and conversion seems to be simple. However, I am not sure if this is just the case with the GPUs being sold in the PCs I have, because it seems to work well in those cases.
To carry “HDMI” signal and use those cheap passive cables, you will need to have a dual mode DP++ port. This is an optional feature and not all of the DP port support such mode. What’s more, the DP Alt mode on USB-C ports is inherently not compatible with such mode so you have to use an active cable anyway on USB-C.
And also this is you get different results with different distros.
I have an adaptor that works when I boot into debian and not when I boot into armbian
I bought on Aliexpress USB-C to DP Adapter which has also PD and it works fine with with the PD supply and DP monitor.
