Nut upsdev - Nov 2009 - usbhid-ups input reports

I want to revive an old discussion. Should we use the contents of  
input reports or not?

A while back, we decided not to use the contents of input reports,  
because there is no guarantee that input report 'n' has the same  
meaning as feature report 'n'. We have not seen any cases so far where  
this is not the case, but as far as we could see, there is nothing in  
the HID PDC specification that doesn't allow this. Therefor, when an  
input report is received, the usbhid-ups driver will now disregard the  
contents and instead proceeds to read the feature report with the same  
index.

I would like to change this behavior. For all report descriptors that  
I could find, the input- and feature reports seem to cover the same  
variables, so there shouldn't be a problem to do this. In case this  
would be a problem, there is still a workaround possible by adding the  
'pollonly' flag to ups.conf, which will make the driver ignore input  
reports altogether.

Any objections?

Best regards, Arjen
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Please keep list traffic on the list

Hi Arjen,

2009/11/30 Arjen de Korte <nut+devel at
de-korte.org>:
> I want to revive an old discussion. Should we use the contents of input
> reports or not?
>
> A while back, we decided not to use the contents of input reports, because
> there is no guarantee that input report 'n' has the same meaning as
feature
> report 'n'. We have not seen any cases so far where this is not the
case,
> but as far as we could see, there is nothing in the HID PDC specification
> that doesn't allow this. Therefor, when an input report is received,
the
> usbhid-ups driver will now disregard the contents and instead proceeds to
> read the feature report with the same index.
>
> I would like to change this behavior. For all report descriptors that I
> could find, the input- and feature reports seem to cover the same
variables,
> so there shouldn't be a problem to do this. In case this would be a
problem,
> there is still a workaround possible by adding the 'pollonly' flag
to
> ups.conf, which will make the driver ignore input reports altogether.
>
> Any objections?
I was thinking the same when reading the thread with Thomas...
we may even have a per subdriver flag to force pollonly when we know
it's necessary.

cheers,
Arnaud
-- 
Linux / Unix Expert R&D - Eaton - http://www.eaton.com/mgeops
Network UPS Tools (NUT) Project Leader - http://www.networkupstools.org/
Debian Developer - http://www.debian.org
Free Software Developer - http://arnaud.quette.free.fr/