From 821047c4055cca833c4674f172a9d73003563eb6 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Sat, 1 Mar 2014 15:31:53 +0100 Subject: can: remove CAN FD compatibility for CAN 2.0 sockets In commit e2d265d3b587 (canfd: add support for CAN FD in CAN_RAW sockets) CAN FD frames with a payload length up to 8 byte are passed to legacy sockets where the CAN FD support was not enabled by the application. After some discussions with developers at a fair this well meant feature leads to confusion as no clean switch for CAN / CAN FD is provided to the application programmer. Additionally a compatibility like this for legacy CAN_RAW sockets requires some compatibility handling for the sending, e.g. make CAN2.0 frames a CAN FD frame with BRS at transmission time (?!?). This will become a mess when people start to develop applications with real CAN FD hardware. This patch reverts the bad compatibility code together with the documentation describing the removed feature. Acked-by: Stephane Grosjean Signed-off-by: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde --- Documentation/networking/can.txt | 6 ------ 1 file changed, 6 deletions(-) (limited to 'Documentation/networking') diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt index f3089d42351..0cbe6ec22d6 100644 --- a/Documentation/networking/can.txt +++ b/Documentation/networking/can.txt @@ -554,12 +554,6 @@ solution for a couple of reasons: not specified in the struct can_frame and therefore it is only valid in CANFD_MTU sized CAN FD frames. - As long as the payload length is <=8 the received CAN frames from CAN FD - capable CAN devices can be received and read by legacy sockets too. When - user-generated CAN FD frames have a payload length <=8 these can be send - by legacy CAN network interfaces too. Sending CAN FD frames with payload - length > 8 to a legacy CAN network interface returns an -EMSGSIZE error. - Implementation hint for new CAN applications: To build a CAN FD aware application use struct canfd_frame as basic CAN -- cgit v1.2.3-70-g09d2