Von: Lava-users <lava-users-bounces@lists.lavasoftware.org> Im Auftrag von Tim Jaacks
Gesendet: Montag, 25. Februar 2019 13:11
An: Neil Williams <neil.williams@linaro.org>
Cc: lava-users@lists.lavasoftware.org
Betreff: Re: [Lava-users] External worker devices in LXC / connection to DUTs
>
> > On Fri, 22 Feb 2019 at 17:17, Tim Jaacks <tim.jaacks at garz-fricke.com> wrote:
> >
> > > Hello,
> > >
> > > we are trying to add external interfaces on the worker to connect with the
> > > DUTs, for example a 4-port USB-to-RS232 converter. Our DUTs have multiple
> > > RS232 ports which shall be tested using this remote interface.
> > > We have already figured out how to integrate this hardware into the LAVA
> > > environment, so that it can be used within the LAVA LXC (using static_info
> > > in the device dictionary, resulting in the four /dev/ttyUSB* devices being
> > > visible there).
> > >
> > > First question: We need multiple of these converters attached to the
> > > worker. How do we integrate these into LAVA? They all have the same
> > > board_id, vendor_id and product_id. If I specify the board_id in the device
> > > dictionary multiple times, the device is still added only once.
> > >
> >
> > There must be a way to distinguish devices at a udev level or there is no
> > way to identify which devices to add to the LXC. If the converters are not
> > unique, then you can only have one per DUT. You will need to purchase new
> > hardware from a vendor who has spent the extra few cents to register unique
> > IDs.
> >
> > Think about how this would work without LXC - how would your scripts tell
> > these devices apart? How does the kernel tell them apart? Do not rely on
> > USB enumeration, that is known to be unreliable. What is ttyUSB7 today can
> > be ttyUSB9 tomorrow (or more likely at some random time after N resets due
> > to some unexpected change elsewhere or just because it could).
> >
> > Without solving this, all other questions are moot.
> >
>
> I get that point, thanks Neil. However, even if I have only one of these devices, it adds four /dev/ttyUSB* device nodes, so all of
these are available in my LXC. The order here is deterministic, because it’s one single driver instance which registers them. How do I tell LAVA which of my DUTs is connected to which of these devices?
>
This question is still relevant. Any hints on this?
> >
> > >
> > > Second question: We need a way to specify to which of the /dev/ttyUSB*
> > > ports a certain RS232 port of the DUT is connected. The place where I would
> > > assume to put such information is the device dictionary. But how can we
> > > access this information within a LAVA test shell?
> > >
> >
> > Solve the first issue first - without unique identifiers, there will only
> > be one /dev/ttyUSB* device added to the LXC in the first place.
> >
> >
> >
> > >
> > > The documentation specifies some similar mechanism for energy probes:
> > >
> > >
> > > https://validation.linaro.org/static/docs/v2/admin-lxc-deploy.html?highlight=device_info.#other-related-devices
> > >
> > > It says "Devices which are not directly attached to the worker can also be
> > > supported, for example energy probes which communicate over the network".
> > >
> >
> > These are alternative energy probes which have dedicated values.
> >
> >
> >
> > > As far as I can tell from the code, though, this seems to be a hard-coded
> > > feature without any possibility of adding other custom hardware. Is that
> > > correct?
> > >
> > > If yes, why isn't there a generic mechanism to supply static_info from the
> > > device dictionary in the LAVA test shell? Or is there?
> > >
> >
> > Not currently.
> >
> >
> >
> > >
> > > How can we implement our scenario described above using LAVA?
> > >
> > > Mit freundlichen Grüßen / Best regards
> > > Tim Jaacks
> > > DEVELOPMENT ENGINEER
> > > Garz & Fricke GmbH
> > > Tempowerkring 2
> > > 21079 Hamburg
> > > Direct: +49 40 791 899 - 55
> > > Fax: +49 40 791899 - 39
> > > tim.jaacks at garz-fricke.com
> > > www.garz-fricke.com
> > > WE MAKE IT YOURS!
> > >
> > > Sitz der Gesellschaft: D-21079 Hamburg
> > > Registergericht: Amtsgericht Hamburg, HRB 60514
> > > Geschäftsführer: Matthias Fricke, Manfred Garz, Marc-Michael Braun
> > >
> > >
> > >
> > >
> > >
> > > _______________________________________________
> > > Lava-users mailing list
> > > Lava-users at lists.lavasoftware.org
> > > https://lists.lavasoftware.org/mailman/listinfo/lava-users
> >
> >
> >
> > --
> >
> > Neil Williams
> > =============
> > neil.williams at linaro.org
> > http://www.linux.codehelp.co.uk/
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Mit freundlichen Grüßen / Best regards
Tim Jaacks
DEVELOPMENT ENGINEER
Garz & Fricke GmbH
Tempowerkring 2
21079 Hamburg
Direct: +49 40 791 899 - 55
Fax: +49 40 791899 - 39
tim.jaacks@garz-fricke.com
www.garz-fricke.com
WE MAKE IT YOURS!
Sitz der Gesellschaft: D-21079 Hamburg
Registergericht: Amtsgericht Hamburg, HRB 60514
Geschäftsführer: Matthias Fricke, Manfred Garz, Marc-Michael Braun