16.04: issues with wireless on MacBook Pro
kassube at gmx.net
Mon Jul 4 04:49:49 UTC 2016
Paul Smith wrote:
> On Fri, 2016-07-01 at 07:28 +0200, Nils Kassube wrote:
> > > If I run iwevent I can see a message "Scan request completed"
> > > exactly
> > > every 2 minutes. I don't know if that's normal or not. No other
> > > messages are shown. dmesg shows no messages since I booted.
> > That looks to me like network manager scans for other networks every
> > two minutes. As you have an a/b/g/n wireless card, it will scan
> > all available channels on the 2 GHz and on the 5 GHz bands which
> > takes quite some time. On my machine with an a/b/g/n card a scan
> > takes ~14 seconds with only 4 access points visible. And during
> > this time it doesn't transfer the data you're intersted in.
> > That was the reason why I abandoned network manager many years ago
> > - especially video chat with ekiga was unacceptable with regular
> > sound drops. Since then I use wicd on all machines and never had
> > such a problem again.
> Thanks for this note. It put me on the right track, and I was able to
> find a solution using Network Manager. Apparently if you configure
> the wireless connection with the specific MAC address of your
> wireless access point in the BSSID field, then Network Manager won't
> look for "better" connections.
That's interesting - I think I have to try that option and see if it
works for me as well.
> I still see the scan requests going by every 2 minutes but it doesn't
> seem to interrupt my network access. I would like an option to force
> scanning off altogether: 99.9% of the time when I use my laptop I
> actually _don't_ want to roam and I know exactly which network I want
> to connect to. But, as long as it doesn't interrupt my work it
> doesn't bother me much.
The option to disable scanning while connected would be great, and I
suppose that is the usual situation for many users.
> It appears this is something of a
> contentious issue in the Network Manager world, unfortunately. The
> author(s) refuse to allow this configuration option and insist that
> if wifi drivers were written correctly it would not be necessary.
> However this doesn't help people like me who have no choice
> (company-provided hardware) but to use proprietary wireless drivers
> which apparently aren't written correctly.
That was my impression as well and therefore I switched to wicd.
> I want to use Network Manager because (a) it's built in and easy, and
> (b) I need to use various VPNs, and wicd (from what I can tell)
> doesn't support this yet.
Right, wicd doesn't have that many features like network manager, but
actually I don't need them. OTOH I would prefer network manager anyway
because it is the standard tool coming with the system.
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