Wily raconteur

Why btop Detaches My Onboard Ethernet Card The Intel I225-V at PCI 0a:00.0 had been blacklisted in /etc/modprobe.d/ for two years. A short comment above the blacklist line read: "The NIC is broken on Linux". I had bought a USB 2.5G dongle and forgotten about the onboard NIC, the way you do when there are other problems. This is the story of what was actually wrong with it. The hardware in question is a rev 03 die, the B3 stepping Intel shipped specifically to fix the well-known I225-V 2.5G connectivity bug from earlier revisions. That earlier bug shows up as link drops, renegotiations, and noisy dmesg around link state. The signature in this post is different: config space alive, MMIO dead, no link retraining, no AER. If you saw "I225-V" and "2.5G" in the title and assumed the famous one, this is a different defect. The trigger Thirty-six hours into uptime, dmesg printed this. The Modules linked in line, the register dump, and the ? -marked speculat...

A firmware update broke my fiber WAN. The device that broke it reported itself perfectly healthy on every check I could think of. Here is how I found the fault, the seven wrong turns I took first, and how far the evidence actually goes. The setup The uplink is an HSGQ/ODI M110 GPON SFP stick , a Realtek RTL9602C SoC inside a transceiver. Firmware V1.0-220923 works. Firmware V1.1.8-240408 reproducibly kills WAN. Same fiber, same OLT, same hardware. Only the firmware string differs. The HSGQ/ODI M110 GPON SFP stick. The cruel part is that the broken firmware looks fine. The ONU reaches O5, the GPON operational state (G.984.3): registered with the OLT, ranged, all alarm flags clear, GEM port mappings present. Every surface check is green. No service traffic reaches the host. One symptom sent me the wrong way early. Link-local control frames, LLDP (multicast) and MNDP (broadcast), still showed up in the router's traffic sniffer while service unicast did not. I read that as a host-...