# RPI 4 HDMI video output flickering
**URL:** https://dietpi.com/forum/t/rpi-4-hdmi-video-output-flickering/15466
**Category:** Troubleshooting
**Created:** [3 January 2023 22:09 UTC](https://dietpi.com/forum/t/rpi-4-hdmi-video-output-flickering/15466 "2023-01-03T22:09:49Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@jaum20](https://dietpi.com/forum/u/jaum20)
#### Post date: [3 January 2023 22:09 UTC](https://dietpi.com/forum/t/rpi-4-hdmi-video-output-flickering/15466/1 "2023-01-03T22:09:50Z")
#### Required Information
- DietPi version: v8.12.1
- Distro version: Debian GNU/Linux 11 (bullseye)
- Kernel version: Linux DietPi 5.15.76-v8+ #1597 SMP PREEMPT Fri Nov 4 12:16:41 GMT 2022 aarch64 GNU/Linux
- SBC model: RPi 4 Model B (aarch64)
- Power supply used: 5V 3A
- SD card used: SanDisk ultra 16 GB
#### Additional Information (if applicable)
#### Steps to reproduce
1.Turn on the RPI4
2. Turn on Monitor
3. Flickering screen
#### Expected behaviour
No flickering
#### Actual behaviour
the video output started flickering out of the blue. I don’t know if it is a hardware issue, but I suspect it is system related. If I use another SD card that I have with OSMC, it works fine. Monitor is a Samsung 1080p. I tried all 1080p resolution on dietpi-config with not luck. Also tried to add HDMI\_BOOST=7 in boot/config.txt. Tried different HDMI cables. Nothing can make it stop the flickering.
---
### Author:  [@MichaIng](https://dietpi.com/forum/u/MichaIng)
#### Post date: [4 January 2023 06:22 UTC](https://dietpi.com/forum/t/rpi-4-hdmi-video-output-flickering/15466/2 "2023-01-04T06:22:04Z")
Does it make a difference when you enable/disable KMS, either via `dietpi-config` or adding/commenting a line in `/boot/config.txt`
```auto
dtoverlay=vc4-kms-v3d
```
---
### Author:  [@jaum20](https://dietpi.com/forum/u/jaum20)
#### Post date: [5 January 2023 00:10 UTC](https://dietpi.com/forum/t/rpi-4-hdmi-video-output-flickering/15466/3 "2023-01-05T00:10:36Z")
Thank you for your response.
Yes, changing to the vc4-kms-v3d driver make the flickering stop, but also change the resolution. The image look stretched and neofetch shows that the resolution is 1152x864
---
### Author:  [@Jappe](https://dietpi.com/forum/u/Jappe)
#### Post date: [5 January 2023 02:03 UTC](https://dietpi.com/forum/t/rpi-4-hdmi-video-output-flickering/15466/4 "2023-01-05T02:03:40Z")
You can try to change the resolution in the `Display Option` menu with `dietpi-config`.
---
### Author:  [@jaum20](https://dietpi.com/forum/u/jaum20)
#### Post date: [5 January 2023 03:07 UTC](https://dietpi.com/forum/t/rpi-4-hdmi-video-output-flickering/15466/5 "2023-01-05T03:07:31Z")
I had tried this before without success. For some reason I don’t know, it worked now. Thanks
---
### Author:  [@MichaIng](https://dietpi.com/forum/u/MichaIng)
#### Post date: [6 January 2023 06:19 UTC](https://dietpi.com/forum/t/rpi-4-hdmi-video-output-flickering/15466/6 "2023-01-06T06:19:25Z")
The problem is that KMS and resolution are currently mixed in the resolution menu, so KMS is always 1080p and everything else is always non-KMS, which ia bad and there is no reason for this. We need to change this, have a dedicated legacy vs fKMS vs KMS toggle and the resolution menu independently of this.
Means for now it’s beat to choose resolution first, then KMS manually, or resolution manually as well.