RobotChicken0
Posts: 2
Joined: Sun Jul 28, 2019 7:19 am

Only one framebuffer on pi4?

Tue Jan 14, 2020 7:34 pm

What am I missing here, I'm only seeing /dev/fb0 on this pi4?

I want to display photographs to two screens at once using fim (works perfectly on a pi3 with one framebuffer), but even though I've seen references to fb1 on a pi4, I'm not seeing it on mine.

Daniel Gessel
Posts: 82
Joined: Sun Dec 03, 2017 1:47 am
Location: Boston area, MA, US
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Re: Only one framebuffer on pi4?

Tue Jan 14, 2020 8:09 pm

My dual monitor setup has only /dev/fb0 as well. The system console seems to use only one (when I open a virtual console, the two monitors mirror each other), but I can create dumb frame buffers on each with KMS in C.

6by9
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 7707
Joined: Wed Dec 04, 2013 11:27 am
Location: ZZ9 Plural Z Alpha, aka just outside Cambridge.

Re: Only one framebuffer on pi4?

Wed Jan 15, 2020 1:48 pm

Use the DRM/KMS API rather than trying to scribble on th framebuffer.
DRM emulates the framebuffer API, and it only creates a single framebuffer device in that emulation - this is all mainline Linux code, not something Pi specific.
Software Engineer at Raspberry Pi Trading. Views expressed are still personal views.
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