Hi there,
Is there a way to make the USB-C data port of the Radxa Zero 3W offer up a higher maximum current?
I’ve been trying out this VDU on the Radxa Zero 3W. My goodness, the screen quality is excellent and the touchscreen functionality is impressive… when it works.
The touchscreen functionality is absent unless I plug the VDU’s USB-C cable into the Z3W after booting the Z3W. If I connect the VDU’s USB-C cable to the Z3W and then power up the Z3W, I have to unplug and reconnect the VDU’s USB-C cable in order to make the touchscreen function.
The video output remains excellent in any case. This problem is present whether I use Manjaro, Debian, or Ubuntu. The output of ‘lsusb’ and ‘xrandr’ proves that the touchscreen is visible to the Linux kernel, even when the touchscreen isn’t actually functioning. This tells me that it’s not a software problem.
The problem is not present if I use a Raspberry Pi 4. It is present if I use a Raspberry Pi Zero, which can’t even supply enough power to switch the VDU on. I use the same power supply box each time. This tells me that the hardware itself is probably not defective. It suggests to me that the VDU might be drawing too much current at boot-time, or that the VDU isn’t getting all the current it wants. That would explain why the VDU works perfectly if connected after the computer has booted up but not if it’s connected when the computer is first switched on.
I’ve tried switching the USB port off and on programmatically via third-party tools such as reset_usb.py or usbreset. I’ve not solved the problem yet.
On the Raspberry Pi, it’s possible to add max_usb_current=1 to perhaps hdmi_force_hotplug=1 to /boot/config.txt (the ‘hdmi’ thing would be in case HDMI, not USB, is the problem). Is there an equivalent for Radxa SBCs? If not, is there another way to increase the maximum current that a Radxa SBC can offer to a USB-connected peripheral?
Thank you for your time. I appreciate it.