Hi Marc, On Tue, Jun 28, 2022 at 11:28 AM Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> wrote: > > On 14.06.2022 14:28:14, Dario Binacchi wrote: > > As suggested by commit [1], now the driver uses the functions and the > > data structures provided by the CAN network device driver interface. > > > > Currently the driver doesn't implement a way to set bitrate for SLCAN > > based devices via ip tool, so you'll have to do this by slcand or > > slcan_attach invocation through the -sX parameter: > > > > - slcan_attach -f -s6 -o /dev/ttyACM0 > > - slcand -f -s8 -o /dev/ttyUSB0 > > > > where -s6 in will set adapter's bitrate to 500 Kbit/s and -s8 to > > 1Mbit/s. > > See the table below for further CAN bitrates: > > - s0 -> 10 Kbit/s > > - s1 -> 20 Kbit/s > > - s2 -> 50 Kbit/s > > - s3 -> 100 Kbit/s > > - s4 -> 125 Kbit/s > > - s5 -> 250 Kbit/s > > - s6 -> 500 Kbit/s > > - s7 -> 800 Kbit/s > > - s8 -> 1000 Kbit/s > > > > In doing so, the struct can_priv::bittiming.bitrate of the driver is not > > set and since the open_candev() checks that the bitrate has been set, it > > must be a non-zero value, the bitrate is set to a fake value (-1U) > > before it is called. > > > > The patch also changes the slcan_devs locking from rtnl to spin_lock. The > > change was tested with a kernel with the CONFIG_PROVE_LOCKING option > > enabled that did not show any errors. > > You're not allowed to call alloc_candev() with a spin_lock held. See > today's kernel test robot mail: > > | https://lore.kernel.org/all/YrpqO5jepAvv4zkf@xsang-OptiPlex-9020 > > I think it's best to keep the rtnl for now. The rtnl_lock() uses a mutex while I used a spin_lock. static DEFINE_MUTEX(rtnl_mutex); void rtnl_lock(void) { mutex_lock(&rtnl_mutex); } EXPORT_SYMBOL(rtnl_lock); So might it be worth trying with a mutex instead of rtnl_lock(), or do you think it is safer to return to rtn_lock () anyway? Thanks and regards, Dario > > regards, > Marc > > -- > Pengutronix e.K. | Marc Kleine-Budde | > Embedded Linux | https://www.pengutronix.de | > Vertretung West/Dortmund | Phone: +49-231-2826-924 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- Dario Binacchi Embedded Linux Developer dario.binacchi@xxxxxxxxxxxxxxxxxxxx __________________________________ Amarula Solutions SRL Via Le Canevare 30, 31100 Treviso, Veneto, IT T. +39 042 243 5310 info@xxxxxxxxxxxxxxxxxxxx www.amarulasolutions.com
