jamesh
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Re: Pi 4 4GB- Wifi not working when resolution is set too high

Mon Dec 02, 2019 2:48 pm

Fairly old firmware, have you tried a

sudo apt update
sudo apt full-upgrade

if that doesn;t help, you could try rpi-update.
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skibum
Posts: 14
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Re: Pi 4 4GB- Wifi not working when resolution is set too high

Mon Dec 02, 2019 3:15 pm

jamesh wrote:
Mon Dec 02, 2019 2:48 pm
Fairly old firmware, have you tried a

sudo apt update
sudo apt full-upgrade

if that doesn;t help, you could try rpi-update.
Updated fully and updated firmware with rpi-update as well.

They are now on :-

Code: Select all

pi@pi4-4:~ $ vcgencmd version
Nov 29 2019 18:44:32
Copyright (c) 2012 Broadcom
version aabb1fb5c19d80db268aeccd67b9f4e0f3d48a2a (clean) (release) (start)

and

pi@pi4-4zig:~ $ vcgencmd version
Nov 29 2019 18:44:32
Copyright (c) 2012 Broadcom
version aabb1fb5c19d80db268aeccd67b9f4e0f3d48a2a (clean) (release) (start)

So I'll see how that goes.

Aardappeltaart
Posts: 67
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Re: Pi 4 4GB- Wifi not working when resolution is set too high

Mon Dec 02, 2019 6:48 pm

hippy wrote:
Mon Dec 02, 2019 1:21 pm
Aardappeltaart wrote:
Fri Nov 29, 2019 2:01 pm
Most people out there I've spoken think it is a Raspberry Pi 4 problem and not a faulty HDMI cable.
That's probably because most people have been led to believe that expensive and so-called better HDMI cables are not necessary, are a money-taking scam; cheap cable is just fine, and in most cases it is

That, as they are now finding, isn't the full story. But it's not surprising, when they find their cable which otherwise has never caused a problem before does with a Pi 4B, that they jump to the conclusion it must be a Pi problem rather than a cable problem.
Why I don't use the official cable?
- too short (1m), for my use-case I need 2-3m

BTW I have difficulties running `xrandr` over ssh. Not even after starting X (startX):

Code: Select all

xrandr --display :0
Can't open display :0
Will try the new firmware.

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mahjongg
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Re: Pi 4 4GB- Wifi not working when resolution is set too high

Mon Dec 02, 2019 7:53 pm

The RPF people are aware of the issue that some HDMI video modes generate frequencies that can interfere with WiFi, and, according to this post they are attempting to solve the problem with software:
PhilE wrote:
Mon Dec 02, 2019 6:58 am
Friday's rpi-update firmware release includes a patch to choose an HDMI mode for 2560x1440@60Hz with alternate timing (reduced blanking) to avoid harmonics in the 2.4GHz band.
It is a purely physical problem, meaning it doesn't only happen with an RPI4, it can happen with any system that generates 4K HDMI video, and has 2.4GHz WiFi, and where both signals (for WiFi, and HDMI) are in close proximity to each other.

Diablo2_Fan
Posts: 11
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Re: Pi 4 4GB- Wifi not working when resolution is set too high

Tue Dec 03, 2019 10:21 am

mahjongg wrote:
Mon Dec 02, 2019 7:53 pm
The RPF people are aware of the issue that some HDMI video modes generate frequencies that can interfere with WiFi, and, according to this post they are attempting to solve the problem with software:
Can they do the same "magic" with the USB3 interfere, please? :-))

Aardappeltaart
Posts: 67
Joined: Wed Mar 02, 2016 11:32 am

Re: Pi 4 4GB- Wifi not working when resolution is set too high

Tue Dec 03, 2019 11:07 am

mahjongg wrote:
Mon Dec 02, 2019 7:53 pm
The RPF people are aware of the issue that some HDMI video modes generate frequencies that can interfere with WiFi, and, according to this post they are attempting to solve the problem with software:
PhilE wrote:
Mon Dec 02, 2019 6:58 am
Friday's rpi-update firmware release includes a patch to choose an HDMI mode for 2560x1440@60Hz with alternate timing (reduced blanking) to avoid harmonics in the 2.4GHz band.
It is a purely physical problem, meaning it doesn't only happen with an RPI4, it can happen with any system that generates 4K HDMI video, and has 2.4GHz WiFi, and where both signals (for WiFi, and HDMI) are in close proximity to each other.
Thx for the extra information, I'm glad they working on it.

Does that implicate that:
- using HDMI1 will mitigate the problem
- there can be issues, despite a good shielded HDMI cable

I'm asking that because in my test results the choice of monitor matters more than the cable.

deralbert
Posts: 6
Joined: Wed Nov 06, 2019 4:04 pm

Re: Pi 4 4GB- Wifi not working when resolution is set too high

Wed Dec 04, 2019 10:19 pm

Hi. I also have this problem with Wi-Fi. I have Raspberry Pi model B with 4GB RAM. What have I already done:
1. sudo apt update
2. sudo apt full-upgrade
3. HDMI through interface 01
4. sudo rpi-update

None of this actions helped me, I can not connect to the 5ghz network. I also tried to make the screen resolution smaller (now I have 1920x1080), but that does not help me either. I have original HDMI cables from Raspberry Pi, have official PSU. 2,4ghz Wi-Fi works fine. All 5 ghz networks are visible to my raspberry pi, but when I try to connect with one of them - nothing happens. But I am sure that my 5ghz network is working properly. I can connect to it from my computer or from my smartphone. I have no MAC-Filters on my router enabled.

amgrays
Posts: 4
Joined: Sun Nov 10, 2019 8:52 pm

Re: Pi 4 4GB- Wifi not working when resolution is set too high

Wed Dec 04, 2019 10:51 pm

deralbert wrote:
Wed Dec 04, 2019 10:19 pm
None of this actions helped me, I can not connect to the 5ghz network.
Suggest:
1) Do you have anything connected to USB3?
2) Try REALLY low resolution - easiest way is put following line in config.txt:

Code: Select all

hdmi_safe=1

deralbert
Posts: 6
Joined: Wed Nov 06, 2019 4:04 pm

Re: Pi 4 4GB- Wifi not working when resolution is set too high

Wed Dec 04, 2019 11:22 pm

amgrays wrote:
Wed Dec 04, 2019 10:51 pm
deralbert wrote:
Wed Dec 04, 2019 10:19 pm
None of this actions helped me, I can not connect to the 5ghz network.
Suggest:
1) Do you have anything connected to USB3?
2) Try REALLY low resolution - easiest way is put following line in config.txt:

Code: Select all

hdmi_safe=1
1) Yes, I use Raspberry Pi keyboard + mouse.
2) Done, it didn't help me. The problem persists.

trejan
Posts: 853
Joined: Tue Jul 02, 2019 2:28 pm

Re: Pi 4 4GB- Wifi not working when resolution is set too high

Wed Dec 04, 2019 11:36 pm

deralbert wrote:
Wed Dec 04, 2019 10:19 pm
None of this actions helped me, I can not connect to the 5ghz network
You've got a different issue. This HDMI issue caused problems with 2.4GHz and it was with a specific resolution + channel 1.

trejan
Posts: 853
Joined: Tue Jul 02, 2019 2:28 pm

Re: Pi 4 4GB- Wifi not working when resolution is set too high

Wed Dec 04, 2019 11:41 pm

Diablo2_Fan wrote:
Tue Dec 03, 2019 10:21 am
Can they do the same "magic" with the USB3 interfere, please? :-))
Nope. You need better shielding or use an extension to move the USB 3.0 device further away.

Aardappeltaart
Posts: 67
Joined: Wed Mar 02, 2016 11:32 am

Re: Pi 4 4GB- Wifi not working when resolution is set too high

Thu Dec 05, 2019 9:44 am

skibum wrote:
Mon Dec 02, 2019 3:15 pm


pi@pi4-4zig:~ $ vcgencmd version
Nov 29 2019 18:44:32
Copyright (c) 2012 Broadcom
version aabb1fb5c19d80db268aeccd67b9f4e0f3d48a2a (clean) (release) (start)

[/code]

So I'll see how that goes.
Tried that firmware: HDMI audio was dropped in some files. TV was working fine with sound, so the KODI GUI.

So reverted to get audio back:

Code: Select all

sudo apt-get install --reinstall raspberrypi-bootloader raspberrypi-kernel
vcgencmd version
Sep 24 2019 17:34:30
Now I wanna give it another try, testing WIFI performance, but running rpi-update doesn't do much now:

Code: Select all

 $ sudo rpi-update
 *** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom
 *** Performing self-update
 *** Relaunching after update
 *** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom
 *** Your firmware is already up to date
Did I mess something up?

jdb
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Re: Pi 4 4GB- Wifi not working when resolution is set too high

Thu Dec 05, 2019 1:56 pm

Remove the file /boot/.firmware_revision.
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