On Sat, 10 Oct 2020 16:29:06 +0200 Oliver Hartkopp wrote: > >> diff --git a/net/can/Kconfig b/net/can/Kconfig > >> index 25436a715db3..021fe03a8ed6 100644 > >> --- a/net/can/Kconfig > >> +++ b/net/can/Kconfig > >> @@ -55,6 +55,19 @@ config CAN_GW > >> > >> source "net/can/j1939/Kconfig" > >> > >> +config CAN_ISOTP > >> + tristate "ISO 15765-2:2016 CAN transport protocol" > >> + default y > > > > default should not be y unless there is a very good reason. > > I don't see such reason here. This is new functionality, users > > can enable it if they need it. > > Yes. I agree. But there is a good reason for it. > The ISO 15765-2 protocol is used for vehicle diagnosis and is a *very* > common CAN bus use case. More common than j1939? (Google uses words like 'widely used' and 'common' :)) To give you some perspective we don't enable Ethernet vlan support by default, vlans are pretty common, too. > The config item only shows up when CONFIG_CAN is selected and then ISO > 15765-2 should be enabled too. I have implemented and maintained the > out-of-tree driver for ~12 years now and the people have real problems > using e.g. Ubuntu with signed kernel modules when they need this protocol. > > Therefore the option should default to 'y' to make sure the common > distros (that enable CONFIG_CAN) enable ISO-TP too. I understand the motivation, but Linus had pushed back on defaulting to 'y' many times over the years, please read this: https://lkml.org/lkml/2012/1/6/354 This really must not pop up on his screen as default 'y' when he does an oldconfig after pulling the networking tree..
