On Mon, Apr 6, 2020 at 6:57 PM Kalle Valo kvalo@codeaurora.org wrote:
Sumit Garg sumit.garg@linaro.org writes:
On Mon, 6 Apr 2020 at 18:38, Johannes Berg johannes@sipsolutions.net wrote:
On Mon, 2020-04-06 at 16:04 +0300, Kalle Valo wrote:
Johannes Berg johannes@sipsolutions.net writes:
On Mon, 2020-04-06 at 15:52 +0300, Kalle Valo wrote:
Johannes Berg johannes@sipsolutions.net 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/submittingpatch...
I am still confused, without ieee80211_if_add how can the userspace bring up the interface? (there by calling drv_start())?