买的RK3399的板子，开始7.1的系统是可以用adb的。烧录成8.1之后，adb连接到电脑上之后，就没有usb设备了。再烧录成7.1之后，连接到电脑上，电脑也是没有任何反应。
拔掉和连接usb时候，板子串口是有信息的，但是电脑上没任何反应
rk3399_firefly_mid:/ $ [ 167.819140] fusb302 4-0022: connection has disconnected
[ 167.829421] rockchip-dwc3 usb@fe800000: USB unconnected
[ 167.829478] cdn-dp fec00000.dp: [drm:cdn_dp_pd_event_work] Not connected. Disabling cdn
[ 167.829508] android_work: did not send uevent (0 0 (null))
rk3399_firefly_mid:/ $
rk3399_firefly_mid:/ $
rk3399_firefly_mid:/ $ [ 172.499338] phy phy-ff770000.syscon:usb2-phy@e450.6: charger = USB_SDP_CHARGER
[ 172.627617] fusb302 4-0022: CC connected in CC1 as UFP
[ 172.632394] cdn-dp fec00000.dp: [drm:cdn_dp_pd_event_work] Not connected. Disabling cdn
[ 172.633050] rockchip-dwc3 usb@fe800000: USB peripheral connected
rk3399_firefly_mid:/ $
rk3399_firefly_mid:/ $ [ 175.550945] fusb302 4-0022: PD disabled
请问有大神知道是什么情况么？