Atari2020
Posts: 43
Joined: Sun Sep 01, 2019 8:13 pm
Location: Vancouver

Pi 4 overscan fix has big performance hit

Wed Oct 09, 2019 3:05 am

I have the overscan problem that I ‘fixed’ by commenting out the dtoverlay=vc4-fkms-v3d line in config.txt. It worked but I wondered about a performance hit and I asked about it, but I got no answer.
I recently got the fan for my Canakit case, which I did not know it supported until I got it, and now I can play games without throttling. However they were still slow and laggy and the controls did not work smooth.
I tried using the dtoverlay=vc4-fkms-v3d driver with the overscan and was able to use the menu to start games and I found they ran smoothy and fast. The answer to my question about a performance hit with the old drivers on a Pi 4 is: YES! A big hit. It will make games unplayable.
Freeciv and Flare I can play windowed to avoid the overscan problem, other games like Tux Racer do not matter much. It works a lot better than using the old drivers.
Most apps can be windowed so they are easier to use, but the Desktop cannot be windowed and that is a real problem with icons and info around the screen edges.

If anyone else with the overscan problem is using the old drivers and cant play games, I recommend you try using the new one and find other work arounds for the overscan problem.

6by9
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Re: Pi 4 overscan fix has big performance hit

Wed Oct 09, 2019 6:20 am

Your title is fairly misleading - "Disabling vc4-fkms-v3d on a Pi4 has a big performance hit" would be more accurate. An alternate career in clickbait headline writing may await you!

The latest kernel has support for overscan when using vc4-fkms-v3d.
Yes, disabling vc4-fkms-v3d will have a huge impact on performance as all rendering will be done in software.
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Atari2020
Posts: 43
Joined: Sun Sep 01, 2019 8:13 pm
Location: Vancouver

Re: Pi 4 overscan fix has big performance hit

Wed Oct 09, 2019 7:49 pm

I just did an update and upgrade while using the proper driver in case disabling it would not update files, but I still have overscan, the overscan settings only change the boot screen with the four Raspberries, the desktop does not change. I do have an old TV and had to force 1080 mode at first but that has been fixed a few days ago when I tried it.

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Imperf3kt
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Joined: Tue Jun 20, 2017 12:16 am
Location: Australia

Re: Pi 4 overscan fix has big performance hit

Wed Oct 09, 2019 9:11 pm

What do you mean you had to "force" 1080 mode? A TV should have an EDID which the Pi gets the proper resolution from. It should just plug in and work if you're using HDMI.

Could it be caused by whatever you did to force 1080p?
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Atari2020
Posts: 43
Joined: Sun Sep 01, 2019 8:13 pm
Location: Vancouver

Re: Pi 4 overscan fix has big performance hit

Thu Oct 10, 2019 3:55 am

Imperf3kt wrote:
Wed Oct 09, 2019 9:11 pm
What do you mean you had to "force" 1080 mode? A TV should have an EDID which the Pi gets the proper resolution from. It should just plug in and work if you're using HDMI.

Could it be caused by whatever you did to force 1080p?
What I mean is my TV did not work as expected or as it did with the Pi 3, it was in VGA or some other mode. I changed the config.txt settings to force 1080 mode. I commented out the settings a few days ago after an update and the overscan problem was still there.

I am curious to know how many people have the overscan problem. And why I have it of course.

Atari2020
Posts: 43
Joined: Sun Sep 01, 2019 8:13 pm
Location: Vancouver

Re: Pi 4 overscan fix has big performance hit

Fri Oct 11, 2019 10:29 pm

The latest update to the Kernal fixed my overscan problem! THANK YOU. I feel a bit silly because I just posted about the performance hit with the video driver disabled as a fix. It now works well, I got a third place finish in a trial run of Tux Racer. And the overscan settings work as well.

Because I have been looking, I have noticed that every day almost there are updates. I am sure everyone has been working hard.

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