I’d been having problems connecting my laptop to my router to the Phone Coop using a new network cable that I laid under the floor just after the new heating system was installed. It’s a 1970s building – cat-5 wasn’t installed with the original wiring and mains homeplug networking is tricky on this wiring layout. The growing number of people with WiFi and video senders on my hillside (70% of UK users “never or rarely switch off their broadband wireless routers”) seems to be causing more interference and slow-downs, so it seemed worth installing a wired connection while the floors were up.
The connection seemed to work fine, but then kept stopping for 20 seconds at a time – that’s just long enough to break network connections, but barely long enough to start up debugging tools, let alone get useful output.
I was pretty sure the cable wasn’t at fault – Paul tested it with his fancy test gear when he completed the wiring for me. That left the hardware: my much-hated Belkin F5D7630 and the Realtek 8139 in the bizarre Compaq Evo N1015v. I’ve still not got around to replacing that Belkin and it’s been behaving itself well enough recently, while the Compaq has run smoothly once I actually got Linux onto it.
I found the end of this Ubuntu Forums thread which pointed to this archlinux bulletin board thread which suggested
pnpbios=off pnpacpi=off in the boot options. After adding that, the 20-second network pauses have stopped. But why? The ACPI and BIOS in this laptop are generally troublesome (and it looks like this also happens on some Presarios), but what in particular is going wrong this time? Will I suffer ill effects from switching off PNP options? Time will tell, I guess.