[SOLVED] Waveshare 4.3 flickering

[gkulka]

Hi Everyone,

After some years I'm returning to DIY projects. I build streamer based on RPI 3A+, with Protodac, USB hub, and supercapacitor for filtering. Setup is running on 5A power supply based on LM1084. Case is old&dead Kenwood CD player. It includes Waveshare 4.3'' display connected using DSI and I get flickering issue.

Tested so far:
-different power supply[ RPI micro usb port 3,5A] - no change
-only RPI + screen[nor external boards] + different power supply - no change

That would take hardware problem out of equation, for software:
- Installation performed via RPI Imager
- GPU acceleration in Moode setting is OFF
- from Waveshare FAQ - "sudo rpi-update pulls/6417" - throws error on incorrect tar/zip file
-Changing or adding "dtoverlay=vc4-kms-dsi-waveshare-800x480" in config.txt- no change

What can be done to fix this issue?





Best regards,
Greg

[Nutul]

If the problem is more towards a software one, I would think about refresh rate / refresh requests, hence a software issue.

sudo rpi-update pulls/6417" - throws error on incorrect tar/zip file
this suggests a corrupted download of the tar file... maybe achieving a correct one and installing it could exclude/confirm a driver problem.

also, hardware acceleration off could be the cause, involving more cpu power... but would address this later, after the driver update is successful.

I would focus on this issue getting fixed, first.

[gkulka]

[...]also, hardware acceleration off could be the cause, involving more cpu power... but would address this later, after the driver update is successful.

I would focus on this issue getting fixed, first.

Issue is visible regardless if GPU acceleration is on or off. My shell got little rusty, as I didn't use it since high school, but I'll try to push updates At least I remember that I should use Putty for it

[TheOldPresbyope]

“Be specific to be terrific” was my late wife’s favorite saying.

What do you mean specifically by “flickering”? When does it occur and what does it look like?

Pi models prior to the 4B struggle with the local display even with the official Raspberry Pi 7-inch touch screen (also DSI). 

On my Pi 3B+ with the official touch screen I have to both disable GPU acceleration and downgrade the Chromium browser. Otherwise I see a curious random rapid super-positioning of the old and new screen images as I switch states between, say, playback and configure.

Waveshare is often out of date in its advice. I’d be very cautious about poking at the kernel and driver updates.

Regards,
Kent

[gkulka]

“Be specific to be terrific” was my late wife’s favorite saying.

What do you mean specifically by “flickering”? When does it occur and what does it look like?

Pi models prior to the 4B struggle with the local display even with the official Raspberry Pi 7-inch touch screen (also DSI). 

On my Pi 3B+ with the official touch screen I have to both disable GPU acceleration and downgrade the Chromium browser. Otherwise I see a curious random rapid super-positioning of the old and new screen images as I switch states between, say, playback and configure.

Waveshare is often out of date in its advice. I’d be very cautious about poking at the kernel and driver updates.

Regards,
Kent

At beginning of startup everything looks sharp and stable. Later, I see GUI like this + some ghosts. I think Hsync and Vsync is wrong[had something similar on PC].

[TheOldPresbyope]

I'm confused. That's not moOde's WebUI on a local display.

The background image on the screen looks like the fisherman.jpg image that came with the RPiOS I'm running on my Pi400.

The artifacts I'm seeing in your screen capture are qualitatively different from what we were seeing with the official touch screen.


You can search this Forum for posts related to various Waveshare displays. Be mindful of the many variations of displays Waveshare offers and also of the fact that current moOde builds are based on the Bookworm edition of RaspiOS/Debian. Many posts here (and elsewhere) dealt with Bullseye or even earlier editions and no longer apply.

At this point, I have nothing more to contribute. Sorry. If, in fact, you're seeing your flickering in tests with Bookworm RPiOS then you probably should go directly to the RPi Forums. The RPF sys devs hang out there.

Before I forget, kudos to you for repurposing vintage HiFi gear!




Regards,
Kent

[gkulka]

I'm confused. That's not moOde's WebUI on a local display.

The background image on the screen looks like the fisherman.jpg image that came with the RPiOS I'm running on my Pi400.

The artifacts I'm seeing in your screen capture are qualitatively different from what we were seeing with the official touch screen.


You can search this Forum for posts related to various Waveshare displays. Be mindful of the many variations of displays Waveshare offers and also of the fact that current moOde builds are based on the Bookworm edition of RaspiOS/Debian. Many posts here (and elsewhere) dealt with Bullseye or even earlier editions and no longer apply.

At this point, I have nothing more to contribute. Sorry. If, in fact, you're seeing your flickering in tests with Bookworm RPiOS then you probably should go directly to the RPi Forums. The RPF sys devs hang out there.

Before I forget, kudos to you for repurposing vintage HiFi gear!

Regards,
Kent

You misunderstood me. I have same issue with Moode-same blurry/disorted picture as on screen from RPIOS. Issue is described on Waveshare page, but I cannot apply solution they propose. Update file is not correct, config.txt commands are not accepted. Below you can see how it looks like during startup. Furthermore it takes 2-3min to get something on the screen[I assume its 3A+ with low ram].

[Tim Curtis]

IIRC the minimum RAM spec for chromium is 1GB. Maybe try swapping in a 3B+ or higher and see what happens.

[gkulka]

IIRC the minimum RAM spec  for chromium is 1GB. Maybe try swapping in a 3B+ or higher and see what happens.

Thank you. That was it. Today 4B/2GB arrived and works perfectly.

[TheOldPresbyope]

IIRC the minimum RAM spec  for chromium is 1GB. Maybe try swapping in a 3B+ or higher and see what happens.

Thank you. That was it. Today 4B/2GB arrived and works perfectly.

We both learned something here 

Glad it's working as-is on your Pi 4B.

Regards 
Kent