On Tue, 2019-06-11 at 13:56 +0200, Arnd Bergmann wrote: [...] Looking at the flags again, > #define RMNET_FLAGS_INGRESS_DEAGGREGATION (1U << 0) This one I'm not sure I understand - seems weird to have such a fundamental thing as a *configuration* on the channel. > #define RMNET_FLAGS_INGRESS_MAP_COMMANDS (1U << 1) Similar here? If you have flow control you probably want to use it? > #define RMNET_FLAGS_INGRESS_MAP_CKSUMV4 (1U << 2) This again looks like a hardware specific feature (ipv4 checksum)? Not sure why this is set by userspace. > #define RMNET_FLAGS_EGRESS_MAP_CKSUMV4 (1U << 3) This could be set with ethtool instead, I suppose. johannes