path: root/Documentation
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authorOliver Hartkopp <socketcan@hartkopp.net>2014-03-01 15:31:53 +0100
committerMarc Kleine-Budde <mkl@pengutronix.de>2014-03-03 14:29:52 +0100
commit821047c4055cca833c4674f172a9d73003563eb6 (patch)
tree28246c9f50757df9ea1efcad0c8210f098aa1c14 /Documentation
parent4b5b82274a17f0ebbf02378df2ba7f36a3f5af19 (diff)
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 <s.grosjean@peak-system.com> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Diffstat (limited to 'Documentation')
1 files changed, 0 insertions, 6 deletions
diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt
index f3089d423515..0cbe6ec22d6f 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