[GRLUG] wifi connection drops under Ubuntu

[John-Thomas Richards]

On Thu, Apr 08, 2010 at 07:09:29PM -0400, mailtonick wrote:
> What are you using to manage Wireless connections on the Acer? I had a
> similar issue with Ubuntu a while ago and with Mint recently. I replaced the
> default manager with another. I think it was simply titled "network
> manager". I don't have access to the machine now to confirm. I'll hunt it
> down to verify if you can't find the package.

I'm using NetworkManager.

> On Thu, Apr 8, 2010 at 6:58 PM, John-Thomas Richards <jtr at jrichards.org>wrote:
> > On Thu, Apr 08, 2010 at 06:41:38PM -0400, Michael Mol wrote:
> > > On Thu, Apr 8, 2010 at 6:19 PM, John-Thomas Richards <jtr at jrichards.org>
> > wrote:
> > > > I bought an Acer Aspire One for my wife.  It came with Win7 Starter
> > > > Edition.  W7SE is a dog.  I installed Ubuntu (full, not Netbook Remix)
> > > > on it.  It is much snappier than Win7.  However, wifi does not work as
> > > > well under Ubuntu as it does under Win7.  Win7 shows signal strength
> > > > around 85% and Ubuntu (NetworkManager) shows it around 42%.  Googling
> > > > has revealed that these figures may not be accurate.  I am inclined to
> > > > trust them since Win7 never experiences loss of network connectivity
> > > > whereas Ubuntu experiences frequent drops.
> > >
> > > The actual "quality" measurement isn't so simple as a percentage; the
> > > driver itself will be reporting a signal strength in dB and a noise
> > > strength in dB. Your actual connection quality depends on your
> > > signal-to-noise ratio. That "percentage" is going to be some
> > > calculation based on those two numbers. If you drop into an xterm and
> > > run 'iwconfig (interface)', what does it say?
> >
> > root at djr-laptop:~# iwconfig wlan0
> > wlan0     IEEE 802.11bgn  ESSID:"boston_celtics"
> >          Mode:Managed  Frequency:2.462 GHz  Access Point: 00:18:39:B6:9B:2E
> >          Bit Rate=54 Mb/s   Tx-Power=20 dBm
> >          Retry  long limit:7   RTS thr:-Off   Fragment thr:-Off
> >          Encryption key:ECF6-C681-FC
> >          Power Management:-Off
> >          Link Quality=26/70  Signal level=-84 dBm
> >          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
> >          Tx excessive retries:0  Invalid misc:0   Missed beacon:0
> >
> > > > I disabled power management
> > > > on the wifi card (thinking that perhaps Ubuntu is mistakenly reducing
> > > > the power to it in an effort to save power).  This does not eliminate
> > > > the loss of connectivity.  I am not sure what else to do, but no matter
> > > > what, I cannot tell my wife to just boot into Windows.  Any ideas?
> > >
> > > Watch /var/messages and /var/syslog. There's likely something interesting
> > there.
> >
> > It just lost connection again.  dmesg shows multiple entries of this:
> >
> > [ 1927.216729] ath9k: DMA failed to stop in 10 ms AR_CR=0x00000024
> > AR_DIAG_SW=0x40000020
> >
> > > It's also possible that the Aspire One generates more EMI when running
> > > Ubuntu's drivers and policies than when running Windows' drivers and
> > > policies, based on configuration of the device. It may actually *help*
> > > to be more aggressive on power policies for things like your hard disk
> > > and CPU speed.
> >
> > How could Ubuntu's drivers and policies result in more EMI?
> > --
> > john-thomas
-- 
john-thomas
------
I believe that the first test of a truly great man is his humility. I do
not mean by humility, doubt of his own powers. But really great men have a
curious feeling that the greatness is not in them, but through them. And
they see something divine in every other man and are endlessly, foolishly,
incredibly merciful. -John Ruskin, author, art critic, and social reformer
(1819-1900)