On 2/2/21 10:00 AM, Oliver Hartkopp wrote: >>> IMO, can_frames in the tx path with CAN_ERR_FLAG should be dropped >>> if the driver can't handle them. vcan in this regard is capable of >>> handling those, as does the kvaser usb. >> >> Makes sense. The implementation steps could be: >> - convert can_dropped_invalid_skb() from static inline to >> regular function >> - add check for CAN_ERR_FLAG and enabled CAN_CTRLMODE_TX_ERR >> to can_dropped_invalid_skb() >> > > Which means the vcan has to support CAN_CTRLMODE_TX_ERR too. > >>> I think it's wrong that CAN_ERR_FLAG messages would appear as regular >>> frame on CAN, as happens today if I understood well. >> >> ACK > > What happens if you send a valid CAN frame with CAN_ERR_FLAG set? > > I did not check it but I assume the frame is sent as normal frame and > the echo'ed CAN frame would *only* go through the error message filter > bank in af_can.c. If CAN_CTRLMODE_TX_ERR has been added to the kernel and can_dropped_invalid_skb() is updated, then a CAN frame with CAN_ERR_FLAG set would be either send as an error frame or dropped by can_dropped_invalid_skb(). So it would be echoed only if the driver supports CAN_CTRLMODE_TX_ERR and it's enabled. > This is probably not what we want for 'real' CAN devices, so we might > have to take a look at this too. 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 |
Attachment:
signature.asc
Description: OpenPGP digital signature
