RE: [PATCH v2] can: rcar_canfd: Add Renesas R-Car CAN FD driver

Hi Oliver, Marc,

On 03/08/2016 01:48 PM, Ramesh Shanmugasundaram wrote:

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In fact you provided a CAN driver which is "CAN-FD-only".

Yes. That's the status of current submission.

(...)

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I did try this option earlier but there are two problems with this

method.

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1) Below configuration is not possible

ip link set can0 up type can bitrate 1000000 dbitrate 1000000 fd on

"fd on" -> This is not allowed because CAN_CTRLMODE_FD bit is not set in

ctrlmode_supported.

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2) If I ignore "fd on", my interface MTU stays as CAN_MTU only. If I

have to change the MTU alone to CANFD_MTU using another netlink message,
it again checks ctrlmode_supported where it would fail. I have the option
of providing my own change_mtu function & ignore this check but two
configuration messages are required for my driver alone :-(.

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Both these anomalies are addressed with the current check I have.

Oh - you are right with complaining about this inconsistency.

Can you check my RFC patch for Linux stable I just sent on the mailing
list?
http://marc.info/?l=linux-can&m=145745724917976&w=2

As we are fixing this issue in CAN dev.c, I'll remove this check in ndo_open and set CAN_CTRLMODE_FD flag in ctrlmode & remove the flag in ctrlmode_supported in the next v3 version of the patch.

Are there any further comments on v2 patch please?

Thanks,
Ramesh