When I plug my phone (V20 vs995) into my desktop, I can only transfer data using a USB 2.0 port. It charges faster when connected to a 3.0 port but is not detected (nothing in lsusb or dmesg in Linux, nothing in device manager in Windows). But the 3.0 ports on my laptop work fine, charging the phone and detecting it as expected.
This affects all 3.0 ports on my desktop, front and rear panel. USB 3.0 flash drives work correctly and run at 3.0 speeds so the ports aren’t dead or damaged.
I thought it was the cable at first—not all of the pins are populated on the type-C end, and the type-A end only had the pins for USB 2.0. But I got a shiny new 3.1 gen 2 cable and same symptoms. (Again, behavior is perfect on my laptop with this new cable.)
I’m pretty sure it’s my ancient broke-ass motherboard (GA-970A-UD3P). I’ve already tried playing with the legacy USB/xhci hand-off settings in my UEFI, but no dice. If there are any more troubleshooting steps to take, though, I’d love to know. Syncing my music library at 480 MB/s suuucks.