Amoled screen 5,5" Display problem on RBpi4B

Otherness

Hello,

I bought this amoled screen that is designed for Raspberry pi 4B 8GB: https://www.waveshare.com/5.5inch-HDMI-AMOLED.htm

I have tried all possible versions of Android for Raspberry (LineageOS, Omnirom, Raspand) and Emteria OS now but all Android OS have the same problem, i.e. display is not supported load for this screen.
I tested on my tv screen and Android works well.

I have tried to find the solution which should probably be to add something to the config.txt file but no one so far has been able to help me, also on all forums. If you have a solution for me that would be great!

Thanks for your help,

smieschek

Hi @Otherness ,

Have you followed that guide: https://www.waveshare.com/wiki/5inch_HDMI_AMOLED
It states, like you suspected, the following changes to config.txt:

disable_overscan=1
max_usb_current=1
hdmi_group=2
hdmi_mode=87
hdmi_timings=960 0 190 4 32 544 0 10 10 12 0 0 0 60 0 41000000 3

AntonovE

Hi!

I also met some problems with this screen.

I tried to connect it to a RPi4B 4Gb with Emteria.OS 11.3.0 installed. While booting the latter gets stack at some moment and repeatedly outputs messages shown on the pictures attached. As you can see, sometimes these messages saying something about "zygote_secondary" service, sometimes -- about "cameraserver", "media" and "wificond" services.

To fix it I tried to follow official guide from Waveshare concerning this screen (https://www.waveshare.com/wiki/5.5inch_HDMI_AMOLED ) and inserted these lines of settings:

max_framebuffer_height=1920
max_usb_current=1
config_hdmi_boost=10
hdmi_group=2
hdmi_force_hotplug=1
hdmi_mode=87
hdmi_timings=1080 1 26 4 50 1920 1 8 2 6 0 0 0 60 0 135580000 3

to the end of boot/config.txt file but it didn't help. The only profit it had given that RPi began to use correct resolution of the screen from the very beginning of the boot process and not after few seconds after it how it had been previously.

In addition to this I want to add that the same RPI with the same Emteria.OS installed on it works well with my PC's screen and with another Waveshare screen (with this one https://www.waveshare.com/7.9inch-hdmi-lcd.htm ) and does it out-of-box.

I can try to provide additional information if you need so!

Thank you all for your attention and looking forward for your help!

PS Sorry for bad quality photos 🙁

smieschek

hi @AntonovE ,
The quickest thing you can try is to install beta v11.5.0
We changed quite a few things regarding graphics between 11.3.0 and 11.5.0 and it might just work.

AntonovE

@smieschek Thank you for the advice!

I tried to update my system from v11.3.0 to v 11.5.0 by switching to the Beta level of allowed updates in the Emteria's settings and performing an update by clicking on an appropriate button in the same menu after it. The result is that the system was updated and my 5.5' screen began to work. But in the same time another problem appeared - the display/image began to flicker. It didn't do it while standing still but, if you touch the screen causing movements of some elements of a GUI, a few flickers appeared some time after it. Also it should be mention that all other screens that I tried to connect to the Raspberry with updated Emteria.OS suffered from this problem.

As the second step I tried to make a fresh install of v11.5.0 Emteria on a SDcard using Emteria Installer. The result: flickering dissapeared but the 5.5' screen became unworkable again with the same set of symptoms as shown on the pictures above.

smieschek

@AntonovE I suspect that this issue is not related to the display. Might be similar to: #1088
Do you know if there is a Hotspot in your proximity?

Ryan

I'm seeing the same issue with a Waveshare 4" HDMI Capacitive Touchscreen ( https://www.waveshare.com/product/displays/lcd-oled/lcd-oled-2/4inch-hdmi-lcd-c.htm ) on v11.8.0 (also tried Nightly 13.0.11).

I tried both a stock config.txt as well as switching to vc4-fkms-v3d and specifying the Waveshare provided timings in config.txt but in both instances I got the looping errors AntonovE provided screenshots of.

The same setup boots fine in Raspbian using the provided hdmi_timings and works out of the box with KonstaKang (I assume just based on EDID info).

Any assistance would be greatly appreciated.

smieschek

@Ryan Can you check if the fkms setting is still present in the config.txt?

One thing you can try is to boot a fresh image with an HDMI monitor connected. Connect to the device via adb (adb can be enabled in emteria settings) and in the shell enter "setprop persist.rpi.vc4.force fkms". Afterwards, disconnect HDMI monitor and connect the waveshare.
First try to boot without any changes, if that doesn't work, try to add the timings to the config.txt

Ryan

@smieschek

Just confirmed now...

Flashed v11.8.0 to a microSD card, inserted into the RPi 4, and booted while connected to a Dell monitor (via HDMI). Everything works as expected, got all the setup prompts and started the OS.

Shut down the system and swapped from Dell monitor to Waveshare 4" HDMI Capacitive Touchscreen (no other changes) and the system boot-loops with the same messages shown in the screenshots from @AntonovE. You can find a slow-motion video of the output from the failed boot here...

https://photos.app.goo.gl/CviM9jEyaXCQv1jW6

smieschek

@Ryan Just to make sure, when you had the RPi4 connected to the Dell monitor, did you set the property "persist.rpi.vc4.force" to fkms?

Ryan

@smieschek

Apologies, I'm not sure how I missed the setprop part of your response.

I went back and tested again with the following results:

Booted while connected to Dell HDMI monitor, everything worked as expected.
Ran setprop persist.rpi.vc4.force fkms via adb
While still running, swapped HDMI from Dell monitor to Waveshare monitor. Saw an image but wasn't stable, kept cycling vertically on the screen.
Rebooted and experienced a boot loop again (although resolution seemed to be higher on boot output)
Modified config.txt to include the following at the end of file (from Waveshare):

dtparam=i2c_arm=on
dtoverlay=waveshare-4dpic-3b
dtoverlay=waveshare-4dpic-4b
hdmi_force_hotplug=1 
config_hdmi_boost=10
hdmi_group=2 
hdmi_mode=87 
hdmi_timings=720 0 100 20 100 720 0 20 8 20 0 0 0 60 0 48000000 6

Booted with updated config.txt and still experienced boot loop

Please let me know if there is any additional information I can provide.

smieschek

@Ryan I'm out of ideas right now. Guess I would need the displays here to play around with the settings. Do you have some budget or is it a private project?

Any reason to use this specific display and not e.g. the official RPi Touchscreen?

If you want to proceed with the display on your own, I guess the next step would be to record logs using UART and compare an emteria boot log to the Lineage boot:
https://emteria.com/kb/connect-uart-rpi

Ryan

@smieschek

The project is private (non-commercial) but I could cover the cost of a test unit if it would mean inclusion of support for the screen in question.

The reason I'm using this display is because of space constraints in my particular project (which is being designed to fit within a US dual-gang box.

With regards to the UART logging, is there a recommended USB to UART bridge?

smieschek

@Ryan I see. Covering the unit unfortunately won't cut it 🙁
Any UART bridge should do. We are using ones that have the CP2102 chip