WiFi very slow to connect on boot-up

Hello,

I've modified my 2018.3 build so that the WiFi will start at boot-up and connect to my hotspot with a static IP. However, it seem to take a long time, 3-5 minutes, for the network connect to come up. If I just do /etc/init.d/network restart on the console I can normally connect immediately. Based on the console logs, the loading of the driver is the last thing to occur before getting a login prompt:

[ 5.574698] wifi_pm : 0

[ 5.577185] wifi_pm : 1

[ 5.579987] wilc_sdio mmc1:0001:1: Driver Initializing success

[ 5.589445] WILC POWER UP

[ 5.592105] wilc_sdio mmc1:0001:1: SDIO speed: 50000000

[ 5.598191] wilc_sdio mmc1:0001:1: chipid 003000d0

Has anybody seen this problem?

thanks,

jeff

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zedhed over 6 years ago in reply to jhane +1

Hi Jeff, What machine are you pinging Ultra96 from? Is it the Ubuntu Desktop? If so, is the ARP cache getting cleared under Ubuntu during the Ultra96 reboot? If so, then Ubuntu will have to resolve the…

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0 clem57 over 6 years ago
This is a know bug/feature in Linux. The solution:

Found a solution, it seems that the new kernels are compiled with "Accelerate last non-dyntick-idle CPU's grace periods (RCU_FAST_NO_HZ)" option: Yes

explanation from the Linux kernel source:
This option causes RCU to attempt to accelerate grace periods
in order to allow CPUs to enter dynticks-idle state more
quickly. On the other hand, this option increases the overhead
of the dynticks-idle checking, particularly on systems with
large numbers of CPUs.

If you add
nohz=off
to the kernel line in grub the "NOHZ local_softirq_pending" messages don't show up
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0 jhane over 6 years ago in reply to clem57

Hello,
Thanks for your response but those messages have nothing to do with the wifi problem and are not cause any issue, they were just on the console when I cut-n-pasted the wifi driver logs. Also DHCP is not involved here, notice that I said I set my system up with a static IP on my "private" network so I don't have to deal with dynamic IPs.

jeff
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0 clem57 over 6 years ago in reply to jhane

Sorry missed that static word.
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0 clem57 over 6 years ago in reply to jhane

Sorry missed that static word.
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