search

linux-can / can-utils

Linux-CAN / SocketCAN user space applications
2.42k stars 713 forks source link

Potential error in kernel doc regarding J1939 destination address with PDU1 format #560

Open xile273 opened 3 weeks ago

xile273 commented 3 weeks ago

In the kernel documentation for J1939 in the section about the PGN the following is stated:

"On the other hand, when using PDU1 format, the PS-field contains a so-called Destination Address, which is not part of the PGN. When communicating a PGN from user space to kernel (or vice versa) and PDU2 format is used, the PS-field of the PGN shall be set to zero. The Destination Address shall be set elsewhere."

Shouldn't it be: "When communicating a PGN from user space to kernel (or vice versa) and PDU1 format is used, the PS-field of the PGN shall be set to zero. The Destination Address shall be set elsewhere."?

PDU2 format does not have a destination address, just a group extension.

Or am I misunderstanding something?

See: https://docs.kernel.org/networking/j1939.html

olerem commented 3 weeks ago

Hi @xile273, you are right! Thank you. Do you want to send a patch?

xile273 commented 3 weeks ago

Sure, what address should I send it to? Yours?

olerem commented 3 weeks ago

Addresses: To: Robin van der Gracht robin@protonic.nl Oliver Hartkopp socketcan@hartkopp.net Marc Kleine-Budde mkl@pengutronix.de "David S. Miller" davem@davemloft.net Eric Dumazet edumazet@google.com Jakub Kicinski kuba@kernel.org Paolo Abeni pabeni@redhat.com Jonathan Corbet corbet@lwn.net

Cc: kernel@pengutronix.de
linux-can@vger.kernel.org
linux-kernel@vger.kernel.org

xile273 commented 3 weeks ago

Ok great, thank you! Will do that.

marckleinebudde commented 3 weeks ago

FTR: https://lore.kernel.org/all/20241023145257.82709-1-alexander.hoelzl@gmx.net/