I just discovered a solution to the problem: it is some power-saving configuration that messes up wireless. See: <a href="http://ubuntuforums.org/showthread.php?t=1678098&page=2">http://ubuntuforums.org/showthread.php?t=1678098&page=2</a> . From this thread, I used mhall119's answer: there is a script called /usr/lib/pm-utils/power.d/wireless that doesn't work properly. I created the file /etc/pm/power.d/wireless, wrote the two lines "#!/bin/bash" and "exit 0", and made it executable. This overrides the original script, fixing the wireless problem. Thanks to everyone for the help, and to mhall119 too. <div class="gmail_quote">On Fri, Mar 16, 2012 at 9:56 AM, Lance <<a href="mailto:lancecherrychina@gmail.com">lancecherrychina@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">is there any configure interface about setting the wireless network adapter mode ?<div>just like mmc in windows,you can select it s property and find the option of performance mode.</div> <div>search its tool or command by google, maybe it s helpful.</div><div class="HOEnZb"><div class="h5"> <div> <div class="gmail_quote">On Fri, Mar 16, 2012 at 4:01 PM, Freddy Van Ingelgom <<a href="mailto:freddyek@gmail.com" target="_blank">freddyek@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> It is sad but it is not woking for me. When I boot my Dell on battery I have Wifi working but very poor connection. In fact almost unusable. The moment I plug in the power supply it works just great! Freddy<div> <div> <div class="gmail_quote"> On Fri, Mar 16, 2012 at 12:18 AM, Michael Miles <<a href="mailto:Amiga5@live.com" target="_blank">Amiga5@live.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <div link="blue" vlink="purple" lang="EN-US"><div>Take the battery out then replace and try to start Also I have problems with dell mini 910 with wifiWhen I have the power plugged in no wifi Take off power supply and boot with just battery and it works Try it <div style="border:none;border-top:solid #b5c4df 1.0pt;padding:3.0pt 0in 0in 0in"> From: <a href="mailto:ubuntu-users-bounces@lists.ubuntu.com" target="_blank">ubuntu-users-bounces@lists.ubuntu.com</a> [mailto:<a href="mailto:ubuntu-users-bounces@lists.ubuntu.com" target="_blank">ubuntu-users-bounces@lists.ubuntu.com</a>] On Behalf Of <a href="mailto:freddyEK@gmail.com" target="_blank">freddyEK@gmail.com</a> Sent: Thursday, March 15, 2012 3:39 PM To: Ubuntu user technical support, not for general discussions Subject: Re: Re: Wifi problems: is there a solution ?</div><div><div> When I am on battery Wifi is working, but very poorly! I found a lot of mail on this subject, but no solution until now! In the mean time I discovered that my Grub is still using kernel 3.0.0.12 while the latest update installed 3.0.0.17, I did not remark this earlier and I don't know if there is a connection between the two. I am unable to correct this: update-grub produces a list including the latest kernel, but when I restart the computer 3.0.0.17 is not in the list, it stops at 3.0.0.12? Thanks for the help! Freddy Le , Hans Muecke <<a href="mailto:ubuntu-ml01@filderstadtweather.eu" target="_blank">ubuntu-ml01@filderstadtweather.eu</a>> a écrit : > Am Donnerstag, 15. März 2012, 05:01:51 schrieb Freddy Van Ingelgom: > > > > > Hello, > > > I have a problem with my Dell Inspiron 1750 running Ubuntu 11.10. When on > > > battery, wifi is unusable. I just replaced the battery, but the problem > > > persists. > > > > Have you checked if power management powers down wifi while running on battery > > > > -- > > Talk to you later ... Hans (176 to go) > > > > 2012/03/15 16:20 > > EDDS 151620Z 03005KT CAVOK 17/M01 Q1026 NOSIG > > > > -- > > ubuntu-users mailing list > > <a href="mailto:ubuntu-users@lists.ubuntu.com" target="_blank">ubuntu-users@lists.ubuntu.com</a> > > Modify settings or unsubscribe at: <a href="https://lists.ubuntu.com/mailman/listinfo/ubuntu-users" target="_blank">https://lists.ubuntu.com/mailman/listinfo/ubuntu-users</a> > ></div></div></div></div> -- ubuntu-users mailing list <a href="mailto:ubuntu-users@lists.ubuntu.com" target="_blank">ubuntu-users@lists.ubuntu.com</a> Modify settings or unsubscribe at: <a href="https://lists.ubuntu.com/mailman/listinfo/ubuntu-users" target="_blank">https://lists.ubuntu.com/mailman/listinfo/ubuntu-users</a> </blockquote></div> </div></div> -- ubuntu-users mailing list <a href="mailto:ubuntu-users@lists.ubuntu.com" target="_blank">ubuntu-users@lists.ubuntu.com</a> Modify settings or unsubscribe at: <a href="https://lists.ubuntu.com/mailman/listinfo/ubuntu-users" target="_blank">https://lists.ubuntu.com/mailman/listinfo/ubuntu-users</a> </blockquote></div> </div> </div></div> -- ubuntu-users mailing list <a href="mailto:ubuntu-users@lists.ubuntu.com">ubuntu-users@lists.ubuntu.com</a> Modify settings or unsubscribe at: <a href="https://lists.ubuntu.com/mailman/listinfo/ubuntu-users" target="_blank">https://lists.ubuntu.com/mailman/listinfo/ubuntu-users</a> </blockquote></div>