As the title says: we are having some problems with our USB on a custom developed carrier board for the Verdin. While trying to figure out this behavior we have reproduced the issue on the Verdin Development Board (V1.0B) as well.
So the problem is that USB devices are not recognized when they are inserted after the Verdin has booted. To reproduce this issue on the development board we have disabled the USB hub by removing the jumpers
SODIMM_187. We have connected a USB hub to the USB OTG port of the the development board. Now we observe the following behavior:
- If no USB devices are connected during boot, nothing gets recognized if they are plugged in while the system is running.
- If a USB device is plugged in the HUB, we can add new devices while the system is running and they are recognized. Unplugging and re-plugging is OK, as long as at least 1 device remains plugged in.
- If at some point 0 devices are plugged in, no newly plugged in devices are recognized and the USB port seems dead (until reboot).
This issue seems similar to this question. However here there seems to be an OTG issue. I have tried setting the
dr_mode to host (although this only seems to be affecting the host/peripheral behavior ).
We have a couple of questions regarding this issue:
- Is this the expected behavior?
- How come that the development board does not have this issue when
SODIMM_187jumpers are connected. It seems that this only connects a USB hub, which is similar to our case where we connect a USB hub.
- Is there a software fix, or should be implement a hardware fix?