Grant Grundler <grundler@xxxxxxxxxxxx> > Sent: Tuesday, January 19, 2021 6:03 AM > Subject: Re: [PATCH 3/3] net: usb: cdc_ncm: don't spew notifications [...] > > RTL8156 sends notifications about every 32ms. > > Only display/log notifications when something changes. > > > > This issue has been reported by others: > > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1832472 > > https://lkml.org/lkml/2020/8/27/1083 > > > > ... > > [785962.779840] usb 1-1: new high-speed USB device number 5 using > xhci_hcd > > [785962.929944] usb 1-1: New USB device found, idVendor=0bda, > idProduct=8156, bcdDevice=30.00 > > [785962.929949] usb 1-1: New USB device strings: Mfr=1, Product=2, > SerialNumber=6 > > [785962.929952] usb 1-1: Product: USB 10/100/1G/2.5G LAN > > [785962.929954] usb 1-1: Manufacturer: Realtek > > [785962.929956] usb 1-1: SerialNumber: 000000001 > > [785962.991755] usbcore: registered new interface driver cdc_ether > > [785963.017068] cdc_ncm 1-1:2.0: MAC-Address: 00:24:27:88:08:15 > > [785963.017072] cdc_ncm 1-1:2.0: setting rx_max = 16384 > > [785963.017169] cdc_ncm 1-1:2.0: setting tx_max = 16384 > > [785963.017682] cdc_ncm 1-1:2.0 usb0: register 'cdc_ncm' at > usb-0000:00:14.0-1, CDC NCM, 00:24:27:88:08:15 > > [785963.019211] usbcore: registered new interface driver cdc_ncm > > [785963.023856] usbcore: registered new interface driver cdc_wdm > > [785963.025461] usbcore: registered new interface driver cdc_mbim > > [785963.038824] cdc_ncm 1-1:2.0 enx002427880815: renamed from usb0 > > [785963.089586] cdc_ncm 1-1:2.0 enx002427880815: network connection: > disconnected > > [785963.121673] cdc_ncm 1-1:2.0 enx002427880815: network connection: > disconnected > > [785963.153682] cdc_ncm 1-1:2.0 enx002427880815: network connection: > disconnected > > ... > > > > This is about 2KB per second and will overwrite all contents of a 1MB > > dmesg buffer in under 10 minutes rendering them useless for debugging > > many kernel problems. > > > > This is also an extra 180 MB/day in /var/logs (or 1GB per week) rendering > > the majority of those logs useless too. > > > > When the link is up (expected state), spew amount is >2x higher: > > ... > > [786139.600992] cdc_ncm 2-1:2.0 enx002427880815: network connection: > connected > > [786139.632997] cdc_ncm 2-1:2.0 enx002427880815: 2500 mbit/s downlink > 2500 mbit/s uplink > > [786139.665097] cdc_ncm 2-1:2.0 enx002427880815: network connection: > connected > > [786139.697100] cdc_ncm 2-1:2.0 enx002427880815: 2500 mbit/s downlink > 2500 mbit/s uplink > > [786139.729094] cdc_ncm 2-1:2.0 enx002427880815: network connection: > connected > > [786139.761108] cdc_ncm 2-1:2.0 enx002427880815: 2500 mbit/s downlink > 2500 mbit/s uplink > > ... > > > > Chrome OS cannot support RTL8156 until this is fixed. > > > > Signed-off-by: Grant Grundler <grundler@xxxxxxxxxxxx> Reviewed-by: Hayes Wang <hayeswang@xxxxxxxxxxx> Best Regards, Hayes
