Re: Slow mobile broadband detection

[Dan Williams <dcbw redhat com>]

On Tue, 2011-06-14 at 22:33 +0200, dave guandalino wrote:
> 2011/6/14  <perazim portugalmail pt>:
> > I had a similar problem several weeks ago and it turned out all I had to do
> > was
> > upgrade the kernel. Below is the reply from the list to resolve my problem.
> 
> $ uname -a
> Linux tk 2.6.38-8-generic #42-Ubuntu SMP Mon Apr 11 03:31:24 UTC 2011
> x86_64 x86_64 x86_64 GNU/Linux
> 
> Hi Perazim, probably the issue doesn't depend on a kernel bug - at
> least not the one Dan provided the fix for, as 2.6.38 should have the
> patch applied  now.

Except that patch only works for the 'option' driver, which is where
most 3G modem USB IDs should be added.  If your device's IDs aren't
there, you can't take advantage of the fix.  What are your device's IDs?

Dan

> 
> >
> > Perazim
> >
> > On Thu, 2011-05-12 at 21:29 +0100, perazim portugalmail pt wrote:
> >>
> >> Dan,
> >>
> >> Attached are the messages log and the modem-manager log for the Alcatel
> >> X220.
> >>
> >> Let me know if you need any other info or to test anything.
> >
> > These logs indicate a kernel bug, with a 30 second hang when closing a
> > serial port.  I submitted a patch to the kernel to fix this issue which
> > was accepted for the 2.6.37 kernel:
> >
> > commit 02303f73373aa1da19dbec510ec5a4e2576f9610
> > Author: Dan Williams <dcbw redhat com>
> > Date:   Fri Nov 19 16:04:00 2010 -0600
> >
> >    usb-wwan: implement TIOCGSERIAL and TIOCSSERIAL to avoid blocking
> > close(2)
> >
> >    Some devices (ex ZTE 2726) simply don't respond at all when data is sent
> >    to some of their USB interfaces.  The data gets stuck in the TTYs queue
> >    and sits there until close(2), which them blocks because closing_wait
> >    defaults to 30 seconds (even though the fd is O_NONBLOCK).  This is
> >    rarely desired.  Implement the standard mechanism to adjust closing_wait
> >    and let applications handle it how they want to.
> >
> >    Signed-off-by: Dan Williams <dcbw redhat com>
> >
> > and the ModemManager snapshot you have should have the support necessary
> > here.  What kernel version are you running?
> >
> > Dan
> >
> > _______________________________________________
> > networkmanager-list mailing list
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> >
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