Wifi dropout

jamesB

Hello,

I have a problem where the moodlebox access point drops out often. I have read a few notes about this with rpi 4's and also on the moodlebox forum such as https://discuss.moodlebox.net/d/287-moodlebox-400-wifi-connections-drops-after-each-request

We are running the latest moodlebox 4.1.0
I saw note https://github.com/iiab/iiab/issues/2853 and it appears the conclusion is
Raspberry Pi 4 Model B Rev 1.1 - WiFi firmware 7.45.18 "very occasionally works" (on these 2 RPi 4's)
Raspberry Pi 4 Model B Rev 1.2 - WiFi firmware 7.45.18 "ALWAYS WORKS" (on this RPi 4 anyway)
Raspberry Pi 4 Model B Rev 1.4 - WiFi firmware 7.45.18 "NEVER WORKS" (on these 2 RPi 4's)

Is there something we can do to fix this issue?

Thanks

krause

Hi jamesB,
the software developers for Raspberry Pi OS decided that they will use the minimal WiFi firmware 7.45.241. The MoodleBox release 4.1.0 comes with the Wifi firmware 7.44.241. See https://discuss.moodlebox.net/d/287-moodlebox-400-wifi-connections-drops-after-each-request/18

The WiFi firmware 7.45.18 is an early beta software which could get a better number of WiFi connected mobile devices. Yes, I vote for a maximum number of mobile devices in the MoodleBox too. But version 7.45.18 was not officially released for normal use. See also https://github.com/iiab/iiab/issues/2853#issuecomment-1004570957

Best regards, Ralf

Nicolas

krause The MoodleBox release 4.1.0 comes with the Wifi firmware 7.44.241.

In fact, MoodleBox release 4.1.0 comes with Wifi firmware 7.45.241.

moodlebox@moodlebox:~ $ dmesg | grep brcmfmac
...
[    5.574123] brcmfmac: brcmf_c_preinit_dcmds: Firmware: BCM4345/6 wl0: Nov  1 2021 00:37:12 version 7.45.241 (1a2f2fa CY) FWID 01-5209c09
...

jamesB

Ok. Am I right then that if we are using 7.45.241 then we have wifi that will drop out a lot? A pity - as we plan to use it in a classroom. I thought maybe an external wifi dongle would be a solution - but reading the notes in the forum there seems to be quite a bit of configuration and it may or may not work.

Open to ideas - we tried a wi-fi booster - that didn't help. The class we are running is having issues and so very thankful for any input/ideas ...

best to all

James

jamesB

Would a heartbeat be a workaround - ping every minute using a cron job?
https://raspberrypi.stackexchange.com/questions/27475/wifi-disconnects-after-period-of-time-on-raspberry-pi-doesnt-reconnect

Nicolas

jamesB Honestly, this stackexchange question is so old and the new firmware is so fresh I'm afraid it won't do any difference.

jamesB

Quick update - I disabled power management for uap0 and tried a cron job each minute to ping my Pi as a heartbeat - so it would ping itself

sudo iw dev uap0 set power_save off

added to cron tab

* * * * /bin/ping -c2 -I uap0 10.0.0.1 >/dev/null

results --- still drops out

Thanks

James

Nicolas

jamesB I've read on multiple Raspberry Forum discussions that power management has nothing to do with this.

I'm afraid that such dropouts have to do with (all) the wireless firmwares (not only the minimal one) and some clients. I could myself not replicate it.

I suggest that this is reported here: https://github.com/RPi-Distro/firmware-nonfree.

jamesB

From my side - then wifi on rpi is not so useful. Despite the what is claimed. I have a standard pi on my disk, another in Singapore and another in Cambodia. All three behave the same way using 4.1.0. To replicate - all we have to do is turn it on. So - the solution is not to use wifi and maybe go through a router.

Looking at this .... https://moodlebox.net/en/help/moodlebox-network-topology/

eth0 handles traffic to the moodlebox .... so devices connect to the router and then to moodlebox.

thoughts?

thanks as always

James

jamesB

Update - no idea why - but the identical build moodlebox and Pi that is in a remote village has NO drop out issues so far. My Moodlebox in a wi fi zone with loads of wi fi sources does. I suspect that there must be interference from so many signals - I have selected 6 and 11 as channels and still have the issue but only on my box which is test so I can live with it.

What it maybe - hypothesis - is that the chip on the pi is scanning/finding/swapping/indexing all the asp's around it for potential connection. I can't see a time rhythm however. Frankly, I don't have an answer - a few people have this issue - many don't. It does happen and anything I try is ineffective (powermanagement/cron jobs/signal identity/remove pi from box).

I'm rolling out into remote areas and I'd love to know what is the causes as it will bite me one day. If anyone has any thoughts I'm open to ideas.

I was wondering if the compute module 4 and i/o board with the aerial maybe an idea. Anyone know if the aerial on the compute board boost signal?

Thanks as always

Ratna

jamesB Incidentally just this week I made a fresh MoodleBox 4.1.0 and experienced annoying Wi-Fi signal swings. The client would disconnect and reconnect every minute or so. A Wi-Fi signal analyzer showed another sender on the same channel, channel 11, but very far and very weak. I changed the channel of the MoodleBox to 10 and all became quiet. I can't understand how this weak signal disturbed so much.

krause

As I wrote in https://github.com/moodlebox/moodlebox/issues/199 I had problems with one Raspberry Pi 4B (4GB) and MoodleBox 3.10.0. I wrote a documentation about this error.

With a wifi analyser I could take some screen photos of the wifi signal. I was not able to reproduce this error with another Raspberry Pi 4B (4GB) using the same microSD card. But I got the same error when I was using the first Raspberry Pi 4B (4GB) with a different microSD card and MoodleBox 3.10.0.

Currently with MoodleBox 4.1.0 I don‘t have and problem with both Raspberry Pi 4B (4GB).

Ratna

krause It is your https://discuss.moodlebox.net/d/287-moodlebox-400-wifi-connections-drops-after-each-request/3 post which prompted me to check with a wi-fi analyzer.
;-)

jamesB

I think that makes sense - cheers for the direction. We have a Pi in a remote village - so no background signal. Whereas where I am testing I am covered in asp's. I wonder if the compute module and i/o board with the add on aerial would be better at ignoring/focusing attention - I suspect - no proof - that there is a network cpu loop of "check for access points" and the Pi is spinning its wheels discovering loads of potential networks.

Ratna

jamesB If in your site there are no other wi-fi signals, interference is not possible. Still, keep in mind that smart-phones may switch on their hotspots, even if they have no mobile Internet. I don't know why people would do it, technically possible though.

Sorry, I don't know the other hardware you mentioned. https://www.raspberrypi.com/products/compute-module-4/?variant=raspberry-pi-cm4001000 says "Available in 32 variants, with a range of RAM and eMMC Flash options, and with or without wireless connectivity". What is the exact variant you use?

I don't think https://www.raspberrypi.com/products/compute-module-4-antenna-kit/ will change the number of simultaneous devices the Pi will support as an access point, that limit is in the Pi's firmware. The antenna will simply extend the range. For an authoritative answer you might have to ask in Raspberry Pi forums.

krause

The Raspberry Pi Compute Module 4 will have exactly have the same wifi as the Raspberry Pi 4B. It has the same processor, the same wifi chip, the same antenna, and the same software. What should be different?

My problem documentation https://github.com/moodlebox/moodlebox/issues/199 could no be verified by anybody else. Only one of my Raspberry Pi 4B had this problem and the other worked fine. I reinstalled the image to the microSD with no better result. With an older image the problem was fixed and also with the next image. It was frustrating. I could not find the reason for the problems with this Raspberry Pi and the MoodleBox image 3.10.0.

@jamesB: Perhaps you should try the older MoodleBox image 4.0.0. https://moodlebox.net/de/news/version-4.0.0/ and update the Moodle version to Moodle 3.11.5+ https://moodlebox.net/en/help/moodle-version-update/ . The more older MoodleBox version 3.12.0 does not use the current wifi firmware and connects only to a few mobile devices.

I can‘t say if you get better results if you update the Raspberry Pi OS to the last release. https://moodlebox.net/en/help/how-to-upgrade-the-moodlebox/ … in this case the Raspberry Pi OS will get the latest updates for the operating system. But it also overwrites the wifi setting for the minimal wifi driver and you can connect only a few mobile devices. For a test it could be a good idea … if you get a stable wifi signal then you can reactivate the minimal wifi driver.

@Nicolas: we should try to lock the minimal wifi driver so the os update process ca‘t set the normal wifi driver.

Nicolas

krause @Nicolas: we should try to lock the minimal wifi driver so the os update process ca‘t set the normal wifi driver.

~~As of MoodleBox image 4.1.0, this is already the case, see https://github.com/moodlebox/moodlebox/issues/235.~~

In fact, it seems that this is not enough. The soft link is changed during firmware updates 😠 (which is kind of dumb). I've indeed to provide a automatic way to replace the soft link at startup. See https://github.com/moodlebox/moodlebox/issues/244.

Meanwhile this is the way to fix it manually:

cd /lib/firmware/brcm/
sudo ln -sf ../cypress/cyfmac43455-sdio-minimal.bin brcmfmac43455-sdio.bin

krause

Nicolas I tested the update of the Raspberry Pi OS with MoodleBox 4.1.0 because I wanted to see if my Android tablet connects better with the latest software https://discuss.moodlebox.net/d/254-mobile-app/18 .
After the update I had to relink the minimal driver manually. Yes, I did the same as you wrote.

I think that the update process deleted and reinstalled a lot of files in the firmware folder. A lot of files are dated on Jan 14th, 2022 - 21:35.

Ratna

Nicolas This discovery comes a bit too late for me. Just today I had the chance to test a fresh MoodleBox 4.1.0 on Pi 3B+ in a small gathering. The maximum number of wireless clients we could connect was just 10!