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. Bjørn
