Herbaldew
Posts: 44
Joined: Wed Feb 07, 2018 2:59 pm
Location: US Mid-Atlantic

Pi 4 WiFi Troubles

Thu Jul 18, 2019 6:22 pm

Received my new Pi 4 2gb a few days ago but the cord wasn't long enough. I did play with it long enough to see everything worked fine and was really impressed with the speed.

Received a micro to hdmi adapter today so I could use my original cable. Hooked up and all was fine.

A couple reboots later and the WiFi seems to have quit - it won't even make an attempt to connect (3b+ and everything else still connects fine).

Reset the router a few times and have done several fresh image starts on the Pi 4. WiFi still won't even attempt to connect.

Any ideas on what to check before I return it?

Thanks


Edit: "it won't even make an attempt to connect" - that is importing my wpa_supplicant.conf as I have always done. Just tried a fresh untouched image and went through the first run wizard and it does see the network but when it tries to connect, it gives a pop up that says it failed to connect.
Last edited by Herbaldew on Thu Jul 18, 2019 6:51 pm, edited 1 time in total.

timg236
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 253
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Re: Pi 4 WiFi Troubles

Thu Jul 18, 2019 6:50 pm

Please can you check the output of dmesg to see if there are any Wi-fi or SDIO messages.
It might also be useful to know what channels the access point is using and whether it’s 5ghz

Herbaldew
Posts: 44
Joined: Wed Feb 07, 2018 2:59 pm
Location: US Mid-Atlantic

Re: Pi 4 WiFi Troubles

Thu Jul 18, 2019 7:24 pm

dmesg.zip
(9.23 KiB) Downloaded 20 times
I don't see anything - dmesg output attached.

My router is both 2.4 and 5g. My Pi 3+ only connects on 2.4 but this Pi 4 had been connecting on 5.

2.4 channel is set to auto, 5 channel is 153.


Edit: The dmesg output is while booting on a USB SSD, though when I did the "untouched image" I mentioned above that was on SD without the SSD attached.

Herbaldew
Posts: 44
Joined: Wed Feb 07, 2018 2:59 pm
Location: US Mid-Atlantic

Re: Pi 4 WiFi Troubles

Fri Jul 19, 2019 3:51 pm

After much ado I have found the problem - 5g WiFi.

Is there anyway to disable 5g or am I going to have to figure out how to block it on the router just for the Pi so that my other 5g devices can still use 5g?

andrum99
Posts: 927
Joined: Fri Jul 20, 2012 2:41 pm

Re: Pi 4 WiFi Troubles

Fri Jul 19, 2019 9:20 pm

Herbaldew wrote:
Fri Jul 19, 2019 3:51 pm
After much ado I have found the problem - 5g WiFi.

Is there anyway to disable 5g or am I going to have to figure out how to block it on the router just for the Pi so that my other 5g devices can still use 5g?
My router is 2.4GHz and 5GHz as well. I have them using different SSIDs as I want certain devices on just 5GHz. You could try split SSIDs.

pfletch101
Posts: 543
Joined: Sat Feb 24, 2018 4:09 am
Location: Illinois, USA

Re: Pi 4 WiFi Troubles

Fri Jul 19, 2019 11:59 pm

Herbaldew wrote:
Fri Jul 19, 2019 3:51 pm
After much ado I have found the problem - 5g WiFi.

Is there anyway to disable 5g or am I going to have to figure out how to block it on the router just for the Pi so that my other 5g devices can still use 5g?
Could you explain your analysis of your problem in more detail? Your solutions seem somewhat drastic!

Herbaldew
Posts: 44
Joined: Wed Feb 07, 2018 2:59 pm
Location: US Mid-Atlantic

Re: Pi 4 WiFi Troubles

Sat Jul 20, 2019 12:59 am

The problem is that with 5 ghz disabled on the router the Pi connects to the 2.4 ghz fine. Turn the 5 ghz back on and the Pi will only connect around 1 out of 15 boots. It sees the SSID just doesn't connect. I also noticed when it does connect to 5 ghz, that the Pi indicates such but the router shows it connected to 2.4 ghz. Nighthawk R7500V2. I think the speed test per Chromium/Xfinity test page confirms it is connected to 5 ghz as I got around 100 Mbps on 5 ghz and only 5 Mbps on 4 ghz. Maybe the router at fault? Though other 5 ghz devices work fine.

It's not the signal - this is my iPhone sitting on top of the Pi:

Image

I did find that if one chooses Russia as the WiFi country it doesn't try to connect to 5 ghz and connects to the 2.4 ghz fine. That said, now that I know it is 5 ghz capable I sure would like to be able to use it ;) Oh, researching this I see my Pi 3b+ is also 5 ghz capable but I never saw it connect to it.

pfletch101
Posts: 543
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Location: Illinois, USA

Re: Pi 4 WiFi Troubles

Sat Jul 20, 2019 1:35 am

Herbaldew wrote:
Sat Jul 20, 2019 12:59 am
The problem is that with 5 ghz disabled on the router the Pi connects to the 2.4 ghz fine. Turn the 5 ghz back on and the Pi will only connect around 1 out of 15 boots. It sees the SSID just doesn't connect. I also noticed when it does connect to 5 ghz, that the Pi indicates such but the router shows it connected to 2.4 ghz. Nighthawk R7500V2. I think the speed test per Chromium/Xfinity test page confirms it is connected to 5 ghz as I got around 100 Mbps on 5 ghz and only 5 Mbps on 4 ghz. Maybe the router at fault? Though other 5 ghz devices work fine.

I did find that if one chooses Russia as the WiFi country it doesn't try to connect to 5 ghz and connects to the 2.4 ghz fine. That said, now that I know it is 5 ghz capable I sure would like to be able to use it ;) Oh, researching this I see my Pi 3b+ is also 5 ghz capable but I never saw it connect to it.
Thanks for the longer description. I assume that the 5 GHz subnetwork and the 2.4 GHz subnetwork share the same SSID and password. I have a Ubiquiti router which supports up to three independent networks - my Pis are on one that combines 5 GHz and 2.4 GHz subnetworks in this way. I don't yet have a Pi4, but I just checked my 'workhorse' 3B and my 'development' 3B+, both of which are now running Buster. The + shows a 5G connection, but the best download speed I saw in a few tries was 42 Mb/sec - that may be due to other aspects of its design. The 3B shows only a 2.4 GHz connection, with consistent download speeds around 25 Mb/sec. I have never had connection problems with the 3B+ such as you describe for your 4. I will report back when my 4 arrives and I have set it up.

Herbaldew
Posts: 44
Joined: Wed Feb 07, 2018 2:59 pm
Location: US Mid-Atlantic

Re: Pi 4 WiFi Troubles

Sat Jul 20, 2019 1:55 pm

Update: I ran rpi-update to install the latest experimental kernel and my 5g connection started working perfectly.

I restored my backed up "normal" image expecting the same problem and to my surprise 5g now works perfectly on it. Did a clean install of everything - still perfect.

Did the experimental kernel change something on the board that stuck?


Edit:
Herbaldew wrote:
Sat Jul 20, 2019 12:59 am
researching this I see my Pi 3b+ is also 5 ghz capable but I never saw it connect to it.
I think I just never noticed that it was connecting to 5 ghz ... I hooked it up out of curiousity and it did hook up @ 5g.

Herbaldew
Posts: 44
Joined: Wed Feb 07, 2018 2:59 pm
Location: US Mid-Atlantic

Re: Pi 4 WiFi Troubles

Mon Jul 22, 2019 10:13 pm

It quit connecting to 5 ghz again today. PiShop US is replacing it so hopefully this is the end of this subject.

pat4pi
Posts: 1
Joined: Thu Jul 25, 2019 8:34 pm

Re: Pi 4 WiFi Troubles

Thu Jul 25, 2019 9:09 pm

Just to let you know that you're not the only one, I'm seeing some issues with the built-in 5GHz as well. I have the 4GB RPi4 as part of a desktop kit I got from Vilros a few days ago.

My router produces 2.4GHz and 5GHz networks, and I've always had them as separate SSIDs so I could more easily "see" what was connected to what and to keep my wife/kids/friends on the network(s) that I want them on and no others, so my workaround for now is to setup my wpa_supplicant to include just the SSID for the (working) 2.4GHz network.

I've been using 5GHz with a few other devices (my phone, one laptop, etc.) for years now with this same router with zero problems and awesome speeds.

But my issues with RPi 4's internal 5GHz seem to mirror yours: it seems to be a crapshoot at reboot time, and even if it does miraculously connect, it drops out rather consistently .. and sometimes it may briefly magically reconnect and then it craps out quickly again. Much googling hasn't helped me too much, ostensibly because not too many folks are delving into the details of the Pi4 yet. But I've ruled several of the 'obvious' possible things out: it isn't IPv6 related (same behavior w/ or w/o it disabled), and it isn't heat-related (I have a fan attached to my case [I'm not using the stock case that came with the desktop kit precisely because it doesn't allow for adequate cooling] and a temperature monitor via 'watch' shows it consistently < 50C even when working 'really' hard), all country settings appear correct, no crazy errors being reported, and so on.

I'll post more as I learn more, but at least I have been able to prove to myself that it is stable (albeit at very low data rates it seems) when running at 2.4GHz ... but my 2.4GHz near where I live is horrible since it's so overcrowded (too many people == too many 2.4GHz wifi routers!), so I was (am!) really looking forward to getting the built-in 5GHz to work. My main use case at present for the Pi4 was to see if I could create a simple, fully wireless, put-it-anywhere-in-range, rsync target (ie, a type of simple NAS, if you'd like). In that regard, it only has two connections: the USB-C for power (5V/3A supply), and a SanDisk 500GB drive connected to one of the USB 2.0 ports with a short flexible USB cable (and eventually that Sandisk will be velcro-tape-attached to my case). I'm using stock Raspbian as installed by NOOBS, and I subsequently configured everything to run fully headless via direct ssh command line, with an option to turn on x11vnc (for remote initial login desktop access) and/or tightvncserver for virtual vnc access. I did that to further limit power consumption and heat since no HDMI signals are therefore in play, as both HDMIs are unconnected.

I attached a picture of my simple setup:
nas-rpi4-headless-small.jpg
nas-rpi4-headless-small.jpg (216.08 KiB) Viewed 3179 times
However, since going completely headless, I have not gone back to retest the 5GHz to see if there's any difference now that the HDMI is out of the picture. I can't imagine there would be any nefarious interaction between the two, but who knows. Eventually I'll retry it, but right now I'm in the middle of doing a ~3 day long-term-test just at 2.4GHz to continue to prove that out from a stability perspective. So far so good - I've transferred about 52G out of a planned 400GB or so for my initial rsync tests. I see a slight unexplained creep in swap space (it really shouldn't creep up at all given the nature of my test scheme, but it is) use during the continual transfer, but not much, and so I've been clearing out the page cache every 10GB or so just to play it safe (since my main goal right now is stressing the wifi + storage, as opposed to diagnosing the potential memory usage concern).

Anyhow, I'm hopeful that this can be solved, but if it can't be solved internally, there's still the nuclear option: go to an externally-powered 5GHz dongle via an external powered hub .. but that would really be a shame, and would limit the goal I'd set for a truly "small" low-power high-capacity NAS leveraging both 2.4GHz and 5GHz with just a USB-C power connection featuring the RPi4!

Herbaldew
Posts: 44
Joined: Wed Feb 07, 2018 2:59 pm
Location: US Mid-Atlantic

Re: Pi 4 WiFi Troubles

Fri Jul 26, 2019 12:05 am

Mine never broke the connection once it was established (was connected to monitor via HDMI and running from an SSD).

Wish I could tell you how I was making out with the replacement - they received my return Tuesday morning and not only haven't shipped the replacement, they haven't responded to yesterday's query as to its status either :evil:

MisterEd
Posts: 104
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Location: Huntsville, AL USA

Re: Pi 4 WiFi Troubles

Fri Jul 26, 2019 3:38 am

If your replacement Pi 4 still has problems with WiFi then is it possible you are experiencing interference? You stated that your 5GHz WiFi is set to channel 153.

I have an Android app on my phone called WiEye. With it I can see all the WiFi routers near me. For the 2.4GHz and 5Ghz WiFi band for each it shows the channel each one is broadcasting on. If someone else nearby is using the same channel as you you could trying setting your 5GHz to a different channel.

Herbaldew
Posts: 44
Joined: Wed Feb 07, 2018 2:59 pm
Location: US Mid-Atlantic

Re: Pi 4 WiFi Troubles

Mon Jul 29, 2019 9:02 pm

I did try every available channel with no change.

My replacement Pi has been here for over 48 hours now and so far has been flawless.

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