Re: Raspberry Pi 4B does not detect devices in USB 3.0
Date: Mon, 14 Feb 2022 22:22:33 UTC
> On 14 Feb 2022, at 23:10, Archimedes Gaviola <archimedes.gaviola@gmail.com> wrote: > I just tried my new RPI4 board and it seems to work fine the same as my old board. I just observed that the problem is when my VFD (vacuum fluorescent display) device is connected to either of the two USB 3.0 ports, this device having uplcom(4) driver is not detected. I wonder if the VFD is causing interference - it likely has a high voltage supply and those are notorious for generating electrical noise. > It's a Prolific USB-serial device having PL2303 chipset. However, when plugged-in to USB 2.0 ports, this device is detected and functioning. I can send characters with the echo command and redirect it to /dev/cuaU0 for display without any problem. Other observations when this VFD device is connected to either 3.0 ports, the 2.0 ports will not function i.e. plugging-in any USB devices like my keyboard or my EMV reader. When this device is also connected to either of the 2.0 ports, the other 2.0 port is functioning for other USB devices while 3.0 ports are not. I attached two dmesg outputs when the device is detected with 2.0 ports and undetected with 3.0. I also include kldstat and usbdump. I would be curious if putting the VFD on a longer cable, or wrapping the cable through a ferrite, or using an external hub fixes it. Any of those would give a bit more isolation between the VFD and USB3 hardware. -- Daniel O'Connor "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum