Comment 47 for bug 1385113

"unknown main tag item 0x0" comes from the HID layer, it has nothing to do with Bluetooth or connection stability. It's usually a stray NUL character at the end of the HID descriptor which the kernel safely ignores but still logs. In my own driver development (xpadneo), I just shorten the HID descriptor by one byte if it ends with NUL because the devices I work with are known to NUL-terminate their HID descriptors.

Maybe the kernel should do the same: If the last HID descriptor byte is a NUL-byte, it should simply shorten the HID descriptor by one byte, essentially cutting the offending byte off, and the message would be gone. Other than a log message, it has no consequences in the kernel, it comes from a completely different layer that's not related to Bluetooth at all.