app: PPP fixes for recovery#304
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Looks good. Some questions/suggestions
| static void ppp_data_passing_thread(void*, void*, void*); | ||
| static void sm_ppp_activate_pdp_dwork_fn(struct k_work *work); | ||
| static int ppp_stop(enum ppp_reason reason); | ||
| static void ppp_cmd_fail_return_to_at_mode(void); |
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| static void ppp_cmd_fail_return_to_at_mode(void); |
| } | ||
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| ppp_state = PPP_STATE_STOPPING; | ||
| close_ppp_sockets(); |
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What is the reason to make this earlier? To close them even if the interface closure fails?
Could there still be data coming when ppp_stop has been called?
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I was suspecting that these sockets would have been one reason why closing the interface fails.
They keep forwarding traffic, so it can cumulate data and block the LCP messages going through.
I'm unsure if there was any real effect of this after all, but it does not seem to break anything doing it in this order.
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Decrease LCP timeouts to one second. We don't need to realistically wait for longer on the Serial Modem side. Max retransmits set to 5 times, so total timeout is 5 seconds. Increase PPPD holdoff to twice of that, so it is 10 seconds. This allows enough time for Zephyr side to tear down the connection. Retry the net_if_down() as the first attempt might fail when there is heavy traffic. The LCP packet is still queued, so the second retry just tears down the interface in dormant state, so it does not send the LCP anymore. Lower the PPP thread priority to K_LOWEST_APPLICATION_THREAD_PRIO so it does not block any work queues. Signed-off-by: Seppo Takalo <seppo.takalo@nordicsemi.no>
MarkusLassila
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May 19, 2026
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Decrease LCP timeouts to one second. We don't need to realistically wait for longer on the Serial Modem side. Max retransmits set to 5 times, so total timeout is 5 seconds.
Increase PPPD holdoff to twice of that, so it is 10 seconds. This allows enough time for Zephyr side to tear down the connection.
Retry the net_if_down() as the first attempt might fail when there is heavy traffic. The LCP packet is still queued, so the second retry just tears down the interface in dormant state, so it does not send the LCP anymore.
Jira: SM-326, SM-327