[Dextrose] WiFi vs Suspend

Bernie Innocenti bernie at codewiz.org
Tue Aug 24 22:53:29 EDT 2010

[cc += olpc-devel]

El Wed, 25-08-2010 a las 11:05 +1000, forster at ozonline.com.au escribió:
> OS373pyg
> Wifi is locked up after resume from sleep, must restart.
> I presume this bug is being tracked at dev.laptop.org/ in one of the 4 tickets below

>   http://dev.laptop.org/ticket/10232  WiFi dies on suspended XO-1,os300
>   http://dev.laptop.org/ticket/10092  Networking broken over suspend/resume on os13 for XO-1
>   http://dev.laptop.org/ticket/9960   wake-on-WLAN doesn't always work\ (duplicate)
>   http://dev.laptop.org/ticket/9967   ibertas suspend fails on XO-1 (fixed)

There are a number of unsolved bugs in the libertas kernel driver or in
its fantastically proprietary firmare. If you turned on automatic power
management on an XO-1, you might be seeing this other one:


In short, very rarely the libertas usb8xxx disappears from the USB bus
when it receives certain commands from the driver. Suspend/resume are
known to trigger quite frequently and the mesh also seems to cause it
once or twice per day in a classroom of 30 students.

Because time for debugging was running out, in the latest beta builds I
had to disable both mesh support and automatic power management in the
attempt to get rid of this bug. After one week of testing, the problem
was not reported any more.

If you spot this bug again, could you please:

 * check whether eth0 is still visible with "ifconfig -a"

 * check whether the Marvell 8xxx is still visible with "lsusb"

 * "dmesg >dmesg.out" and attach it to the bug. Dextrose enables
   libertas debug in /etc/rc.local to help diagnose this bug.

This never ending saga brings me back to an exasperated email that David
Woodhouse wrote about 3 years ago, after spending many days in
unfruitful debugging, in which he warned that access to the source code
of the firmware was essential in order to nail down all the obscure
Libertas bugs.

   // Bernie Innocenti - http://codewiz.org/
 \X/  Sugar Labs       - http://sugarlabs.org/

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