A few days ago, I reviewed a USB 3.0 to 2.5 Gbps Ethernet adapter based on Realtek RTL8156B chip in Ubuntu 20.04, and let’s say the reliability and performance were underwhelming. I got some recommendations like changing cables, the MTU size, etc… Playing around with cables did no help, but one comment mentioned the cdc_ncm driver could be the issue, followed by another saying that updating to Linux kernel 5.14 should install the correct r8152 driver… So I just did that:
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sudo apt install linux-oem-20.04d |
This upgraded Linux 5.13 (shipped with Ubuntu 20.04 + HWE) to Linux 5.14, but still no luck as the system kept using the cdc_ncm driver with a half-duplex link:
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jaufranc@cnx-laptop-4:~$ inxi -n Network: Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet driver: r8169 IF: enp2s0f1 state: down mac: 98:28:a6:0f:06:07 Device-2: Qualcomm Atheros QCA9377 802.11ac Wireless Network Adapter driver: ath10k_pci IF: wlp3s0 state: up mac: 70:c9:4e:b7:84:77 Device-3: Realtek USB 10/100/1G/2.5G LAN type: USB driver: cdc_ncm IF: enx1cbfced40321 state: up speed: 2500 Mbps duplex: half mac: 1c:bf:ce:d4:03:21 jaufranc@cnx-laptop-4:~$ uname -a Linux cnx-laptop-4 5.14.0-1022-oem #24-Ubuntu SMP Mon Jan 31 16:00:31 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux |
But then I thought I may have to use udev rules to prevent loading the cdc_ncm driver, and there’s indeed 50-usb-realtek-net.rules in r8152 driver to do just that. So I copied the file in /etc/udev/rules.d/ folder. Since I […]