bjorn@xxxxxxx writes: > Daniele Palmas <dnlplm@xxxxxxxxx> writes: > > Il giorno lun 3 ago 2020 alle ore 10:18 Greg KH > > <gregkh@xxxxxxxxxxxxxxxxxxx> ha scritto: > > > >> Actually, no, this all should be done "automatically", do not change > >> the urb size on the fly. Change it at probe time based on the device > >> you are using, do not force userspace to "know" what to do here, as > >> it will not know that at all. > >> > > > > the problem with doing at probe time is that rx_urb_size is not fixed, > > but depends on the configuration done at the userspace level with > > QMI_WDA_SET_DATA_FORMAT, so the userspace knows that. > > Yes, but the driver "will know" (or "may assume") this based on the > QMI_WWAN_FLAG_MUX flag, as long as we are using the driver internal > (de)muxing. We should be able to automatically set a sane rx_urb_size value > based on this? > > Not sure if the rmnet driver currently can be used on top of qmi_wwan? > That will obviously need some other workaround. > > > Currently there's a workaround for setting rx_urb_size i.e. changing > > the network interface MTU: this is fine for most uses with qmap, but > > there's the limitation that certain values (multiple of the endpoint > > size) are not allowed. > > And this also requires an additional setup step for user/userspace, which we > should try to avoid if possible. > > I'm all for a fully automatic solution. I don't think rx_urb_size should be directly > configurable. And it it were, then it should be implemented in the usbnet > framework. It is not a qmi_wwan specific attribute. Hi Bjørn, You can check cdc_ncm.c. cdc ncm driver set 'rx_urb_size' on driver probe time, and the value read from' cdc_ncm_bind_common() 's USB_CDC_GET_NTB_FORMAT '. and also allow the userspace to modify 'rx_urb_size' by ' /sys/class/net/wwan0/cdc_ncm/rx_max'. > > > Bjørn
