Hi @Mastermind
All I know is that the specific error you pointed to has nothing to do with physical power capability.
The specific failure in Linux "Rejected Configuration due to insufficient available bus power" is strictly due to messaging between host OS and USB drivers, and USB devices downstream. We have seen it, and we had Microchip confirm with us that error is a SW element. I am 100% confident on this. USB Tree View will show you exactly which combination of devices is reporting what power so you can start to isolate the issue. In our experience, it has been Linux drivers working with OpenSource USB devices exposing bugs in various Linux USB drivers... they are not all the same or correct.
OS's do not measure VBUS. If VBUS has an issue, the Hub will handle it for our design, and power cycle the device if there is a fault. In most designs, maybe the power control device may flag the OS there was an overpower event, but that is not where the current reporting comes from.
Please feel free to measure VBUS, I suspect you will not see any perturbations on there indicating low power (even if it is a competitor's product, I have confidence that is not your issue, especially since our dongles do not source USB VBUS for power ... they have the external 5V supply which you provide). VBUS on our designs is only used as a "detect" function for enumeration.
It is possible the linux OS driver for USB enumeration was modified by that device if you installed any device drivers... but I am venturing out of my wheel house... if you can remove any drivers you installed for the SDR radio, and try again, that may help confirm that.
Then, try to add in the SDR radio after enumeration with the MH radio.
All the while, I would get USB Tree View and see what you can observe with the device reporting demands.
Another option I would explore is the configuration of the SDR radio. I wonder if it's possible it is reporting it as a permanently connected device (like an embedded USB device), set for bus powered, and hogging all the resources. Even after you remove it... if it is setup as a permanent connected device, the OS may not be releasing the resources for it. So, uninstalling any drivers may help there.
If you have USB Tree View, you can send the config values (attributes, revision, config, etc reported) to the vendor to ask them to explain the register settings, and if they are correct or not.
Hope I am being clear... I'm not the best writer, nor a SW person, but I am very familiar with USB, and we have had this exact issue before, and learned how to fix it.
