> Robert Dobrowolski <robert.dobrowolski@xxxxxxxxxxxxxxx> writes: > >> From: Rafal Redzimski <rafal.f.redzimski@xxxxxxxxx> >> >> Current implementation updates the mtu size and notify cdc_ncm >> device using USB_CDC_SET_MAX_DATAGRAM_SIZE request about datagram >> size change instead of changing rx_urb_size. >> >> Whenever mtu is being changed, datagram size should also be >> updated. > > Definitely! Thanks for this. But looking at the code I believe you > need to fix the calculation of maxmtu too. It is currently: > > int maxmtu = ctx->max_datagram_size - cdc_ncm_eth_hlen(dev); > > And cdc_ncm_set_dgram_size() updates ctx->max_datagram_size with the new > mtu, meaning that you can only reduce the mtu. We should probably use > cdc_ncm_max_dgram_size() instead here. > > And cdc_ncm_set_dgram_size() takes the datagram size with header as > input (ref the above maxmtu calucalution), so it probably needs to > called as > > cdc_ncm_set_dgram_size(dev, new_mtu + cdc_ncm_eth_hlen(dev)); > > to get it right. I think. None of this is tested on an actual device > yet... Care to test if I'm right, and do a v2 if necessry? > >> Cc: <stable@xxxxxxxxxxxxxxx> > > This should be dropped for net. Ask David to queue it for stable > instead. I usually do that by using a subject prefix like > > [PATCH net,stable v1] ... > > > > > Bjørn > ok, thanks for feedback I will send v2 patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html