[Server-devel] Alas, I'm giving up on Access Point function for XO1.5

[George Hunt]

The kernel which has thinfirm is at:
http://download.unleashkids.org/xsce/downloads/os/xo1.5/kernel-3.3.8_xo1.5-20160102.1250.06CE.8ddad46.i686.rpm

And there's an Internet In a Box image with AP function all set up at:

http://download.unleashkids.org/xsce/downloads/os/xo1.5/160210_xo1.5_ap.img.zip
ready to dd onto an SD card (minus content).

On Sun, Apr 3, 2016 at 4:39 PM, James Cameron <quozl at laptop.org> wrote:

> Thanks, very interesting.
>
> The wireless card contains an ARM processor, and that's what the
> firmware runs on.
>
> Yes, the firmware had proven to be stable when used by Open Firmware
> for NANDblaster function, but Open Firmware uses a subset of the
> commands supported.
>
> On the other hand, Linux uses many more commands, and so is likely to
> expose any undiagnosed problems in the firmware, which cause the card
> to hang and the driver to cease traffic.
>
> Some work was done upstream in the past year for mwifiex/mv8787
> recovery after firmware hang, but I've not noticed any recent work on
> libertas.
>
> My gut feel is that your random observation ping results are missed
> receive interrupts; a packet is being received late just after the
> system sends the card an unrelated command, and you might observe a
> response to tuning of the ping interval.
>
> Do you have your latest kernel source available anywhere?
>
> On Sat, Apr 02, 2016 at 11:44:03AM -0700, George Hunt wrote:
> > The recent SD cards are so cheap, and wikipedia in various languages is
> such a
> > good replacement for the encyclopedia I devoured as a kid, I spent a few
> weeks
> > on this project.
> >
> > The results were mixed, but just not good enough. The XO1.5 can act as a
> > gateway for a few minutes, or  a few hours (with apparently random
> delays to
> > the point of failure). But eventually, the libertas thinfirm driver, or
> > firmware, gets to be unresponsive, and only a reboot will correct the
> > situation.
> >
> > History
> > The libertas AP function was developed by OLPC in the 2010 timeframe
> (and used
> > successfully by openfirmware for flashing many XO at a time). I'm not
> clear
> > whether "thinfirm" firmware was generated by marvel, or modfied by
> outside
> > consultant, cozybit under nondisclosure agreement., This firmware may
> have
> > removed some function, but added AP capability. The driver was modified,
> in
> > order to add the sdio interface (the OLPC motherboard uses SDIO interface
> > rather than the pre-existing usb driver interface). The thinfirm driver
> (with
> > USB interface) has been upstreamed, and accepted into the kernel.  But
> the SDIO
> > interface modifications to the driver have not. More recently discovered
> sdio
> > code has not been tried (2) -- or maybe it's the same in a different
> package.
> >
> > Olpc documentation of the AP function existed, and I tried to follow the
> > instructions (1)(4)(7)
> >
> > Jerry Vonau found a patch for sdio interface to thinfirm, which was the
> one I
> > tested (5). If I were to continue, I'd probably try the patch at (2)
> since it's
> > more recent.
> >
> > There are references to setting the libertas_tf driver into debug mode,
> which I
> > did not pursue, since I'd need to learn a lot more about wireless
> protocols, to
> > make use of the debugging information.(6) But that's probably what I
> would need
> > to do if I continued.
> >
> > Random observation:
> >    if a wifi client is connected to an XO1.5 acting as AP, and both the
> client
> > and the server are set to ping one another, the client ping delays are
> > constant. but the server delays are bi-modal, either 5ms or 230ms.
> >
> >  1. [1]http://wiki.laptop.org/go/Thinfirm_1.5
> >  2. [2]http://www.sleepyrobot.com/?p=160 --
> >  3. [3]
> http://dev.laptop.org/git/users/derosier/wireless-testing/tree/drivers/
> >     net/wireless/libertas_tf
> >  4. [4]http://wiki.laptop.org/go/Libertas_Thinfirmware_HOWTO
> >  5. [5]http://www.spinics.net/lists/linux-wireless/msg55208.html
> >  6. [6]
> http://labs.isee.biz/index.php/How_to_setup_Marvell_88w8686_SDIO_wifi#
> >     How_to_debug_the_libertas_driver
> >  7. [7]http://wiki.laptop.org/go/XO_as_AP
> >
> > References:
> >
> > [1] http://wiki.laptop.org/go/Thinfirm_1.5
> > [2] http://www.sleepyrobot.com/?p=160
> > [3]
> http://dev.laptop.org/git/users/derosier/wireless-testing/tree/drivers/net/wireless/libertas_tf
> > [4] http://wiki.laptop.org/go/Libertas_Thinfirmware_HOWTO
> > [5] http://www.spinics.net/lists/linux-wireless/msg55208.html
> > [6]
> http://labs.isee.biz/index.php/How_to_setup_Marvell_88w8686_SDIO_wifi#How_to_debug_the_libertas_driver
> > [7] http://wiki.laptop.org/go/XO_as_AP
>
> > _______________________________________________
> > Devel mailing list
> > Devel at lists.laptop.org
> > http://lists.laptop.org/listinfo/devel
>
>
> --
> James Cameron
> http://quozl.netrek.org/
>
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