[sf-lug] Ubuntu live CD and wi-fi

Rick Moen rick at linuxmafia.com
Thu Sep 20 00:44:01 PDT 2007

Quoting jim stockford (jim at well.com):

> What do i need to know to help this shy person use a live Ubuntu CD
> and get the laptop's wi-fi system to work and thereby connect to the
> internet?

I have a certain amount of experience at researching PeeCee hardware
chipsets (and thus drivers) for people, especially on laptops.  Recent
example: http://lists.svlug.org/archives/svlug/2007-September/028775.html

So, I can offer a few tips about how one can get such hardware from
direct inspection.  Boot a cutting-edge live CD.  (I personally like to
use the latest Sidux, but whatever....)  Then:

1.  "dmesg | less" is a primary source of information -- but is a pretty
horrific, uber-verbose mess until you're used to it.  The trick is to 
learn to efficiently ignore the 95%+ that you don't understand and has
no proven relevance.  Eventually, your eye learns to zoom in on the
significant bits, like these:

  scsi0 : sym-2.1.17a
  scsi1 : sym-2.1.17a
  blk: queue cfe38174, I/O limit 4095Mb (mask 0xffffffff)
  Vendor: QUANTUM   Model: QM39100TD-SW      Rev: N49

a SCSI hard drive

  Intel(R) PRO/100 Network Driver - version 2.3.43-k1
  Copyright (c) 2004 Intel Corporation
  e100: selftest OK.
  e100: eth0: Intel(R) PRO/100 Network Connection

An Intel PRO/100 series ethernet chip compatible with the e100 driver.

(And like that.)

2.  "lspci | less".  An order of magnitude less horrific, but you still
have to study it and look for the significant bits.  You should be able
to find the south bridge chip (which is important because it's where IDE
(SATA and/or PATA) is served from, the SCSI chip if any, the video chip,
the ethernet chip, the Firewire chip if any, the sound chip, the
Bluetooth chip if any, the WiFi chip if any.

3.  "less /proc/cpuinfo" will tell you about the CPU.  Not too
important, but interestiong.  "less /proc/meminfo" will tell you 
all about what RAM is found.

4.  If X11 is running, then "less /var/log/Xorg.*.log" will, if (as with
dmesg) you wade through huge amounts of mostly irrelevant detail, tell
you more about what video circuitry you have, and what it can do.

5.  Reboot, and go into the motherboard BIOS.  Some screens may give you
useful information about the hardware.

And, of course, the CD itself, if it's a good one, may autoprobe your
hardware and selectively load the drivers you need, which is highly
useful information in itself.  ("lsmod | less" is then useful, if you
look selectively.)

Armed with the list of your significant chipset part numbers (south
bridge, video, sound, ethernet, wireless, etc.), you are now in a much
better position to know what driver problems you'll have, and plan a
path to fix them, e.g., "Oh, damn, looks like that's a SATA CD/DVD
drive.  Looks like the libata driver arrived for that around {pause for
googling} around kernel 2.6.15, and I'm on 2.6.9."

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