Re: [PATCH v5 1/7] can: netlink: allow user to turn off unsupported features

From: Marc Kleine-Budde
Date: Thu Aug 19 2021 - 06:07:50 EST


On 19.08.2021 18:24:27, Vincent MAILHOL wrote:
> On Thu. 19 Aug 2021 at 16:45, Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> wrote:
> > On 15.08.2021 12:32:42, Vincent Mailhol wrote:
> > > The sanity checks on the control modes will reject any request related
> > > to an unsupported features, even turning it off.
> > >
> > > Example on an interface which does not support CAN-FD:
> > >
> > > $ ip link set can0 type can bitrate 500000 fd off
> > > RTNETLINK answers: Operation not supported
> > >
> > > This patch lets such command go through (but requests to turn on an
> > > unsupported feature are, of course, still denied).
> > >
> > > Signed-off-by: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx>
> >
> > I'm planing to send a pull request to net-next today. I want to do some
> > more tests with this series
>
> Ack, I am also preparing a new version. But first, I am just
> waiting for your reply on the tdc-mode {auto, manual, off}. :)

I want to do some proper testing, if it's now working as I'm expecting,
before continuing the discussion. :D

> > but this patch is more or less unrelated,
> > so I can take it in this PR, should I?
>
> FYI, the reason to add it to the series is that when setting TDC to
> off, the ip tool sets both CAN_CTRLMODE_TDC_AUTO and
> CAN_CTRLMODE_TDC_MANUAL to zero (which the corresponding bits in
> can_ctrlmode::mask set to 1). Without this patch, netlink would
> return -ENOTSUPP if the driver only supported one of
> CAN_CTRLMODE_TDC_{AUTO,MANUAL}.

Oh, I see.

> Regardless, this patch makes sense as a standalone, I am fine if
> you include it in your PR.

Why not, reduces the patch amount on your side :)

> Also, if you want, you can include the latest patch of the series as well:
> https://lore.kernel.org/linux-can/20210815033248.98111-8-mailhol.vincent@xxxxxxxxxx/
>
> It's a comment fix, it should be pretty harmless.

Ok, makes sense.

regards,
Marc

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