On Mon, Apr 6, 2020 at 6:57 PM Kalle Valo <kvalo@xxxxxxxxxxxxxx> wrote: > > Sumit Garg <sumit.garg@xxxxxxxxxx> writes: > > > On Mon, 6 Apr 2020 at 18:38, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote: > >> > >> On Mon, 2020-04-06 at 16:04 +0300, Kalle Valo wrote: > >> > Johannes Berg <johannes@xxxxxxxxxxxxxxxx> writes: > >> > > >> > > On Mon, 2020-04-06 at 15:52 +0300, Kalle Valo wrote: > >> > > > Johannes Berg <johannes@xxxxxxxxxxxxxxxx> writes: > >> > > > > >> > > > > On Mon, 2020-04-06 at 15:44 +0300, Kalle Valo wrote: > >> > > > > > > user-space ieee80211_register_hw() RX IRQ > >> > > > > > > +++++++++++++++++++++++++++++++++++++++++++++ > >> > > > > > > | | | > >> > > > > > > |<---wlan0---wiphy_register() | > >> > > > > > > |----start wlan0---->| | > >> > > > > > > | |<---IRQ---(RX packet) > >> > > > > > > | Kernel crash | > >> > > > > > > | due to unallocated | > >> > > > > > > | workqueue. | > >> > > > > > >> > > > > [snip] > >> > > > > > >> > > > > > I have understood that no frames should be received until mac80211 calls > >> > > > > > struct ieee80211_ops::start: > >> > > > > > > >> > > > > > * @start: Called before the first netdevice attached to the hardware > >> > > > > > * is enabled. This should turn on the hardware and must turn on > >> > > > > > * frame reception (for possibly enabled monitor interfaces.) > >> > > > > > >> > > > > True, but I think he's saying that you can actually add and configure an > >> > > > > interface as soon as the wiphy is registered? > >> > > > > >> > > > With '<---IRQ---(RX packet)' I assumed wcn36xx is delivering a frame to > >> > > > mac80211 using ieee80211_rx(), but of course I'm just guessing here. > >> > > > >> > > Yeah, but that could be legitimate? > >> > > >> > Ah, I misunderstood then. The way I have understood is that no rx frames > >> > should be delivered (= calling ieee80211_rx()_ before start() is called, > >> > but if that's not the case please ignore me :) > >> > >> No no, that _is_ the case. But I think the "start wlan0" could end up > >> calling it? > >> > > > > Sorry if I wasn't clear enough via the sequence diagram. It's a common > > RX packet that arrives via ieee80211_tasklet_handler() which is > > enabled via call to "struct ieee80211_ops::start" api. > > Ah sorry, I didn't realise that. So wcn36xx is not to be blamed then, > thanks for the clarification. > > -- > https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches I am still confused, without ieee80211_if_add how can the userspace bring up the interface? (there by calling drv_start())?
