Re: [RFC] [PATCH v4] can: fix handling of unmodifiable configuration options

[Oliver Hartkopp <socketcan@hartkopp.net>]

On 03/21/2016 04:19 PM, Ramesh Shanmugasundaram wrote:

>> The only thing I was not sure about when forcing static ctrlmodes to be
>> set was the fact that you would need to set fd-non-iso for the MCAN
>> controller setup - even when you only configure it for CAN2.0 traffic:
>>
>> ip link set can0 type can bitrate 100000 -> ok
>>
>> ip link set can0 type can bitrate 100000 one-shot on -> fail
>
> Oh! I checked for M_CAN but only the config above this. Good that you spotted.
>
>>
>> ip link set can0 type can bitrate 100000 one-shot on fd-non-iso on -> ok
>>
>> To be consistent with 'static ctrlmodes have to be provided' it looks ok.
>> But from a CAN2.0 perspective it looks confusing.
>
> Definitely.
>
>>
>> I wonder if it makes sense to handle this *special* case not to force fd-
>> non-iso when the controller won't get into FD mode. What do you think?
>
> Yes, I agree. Non-ISO only mode will eventually phase out and having a "special" case for this sounds logical.
>

Ok. I'll put this special handling into can_changelink() and will post 
an update (v5).

Thanks,
Oliver