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Bram avatar Ubuntu

fbset has no effect

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Bram

I have added my username to the video group, and this allows me to open and use the /dev/fb0 device. So far so good.

But when I try to change the resolution using fbset(1) nothing happens. There are no errors, but there is no change of video mode either.

I use this on a virtual text console.

$ fbset -v 640x480-72
Linux Frame Buffer Device Configuration Version 2.1 (23/06/1999)
(C) Copyright 1995-1999 by Geert Uytterhoeven

Opening frame buffer device `/dev/fb0'
Reading mode database from file `/etc/fb.modes'
Using video mode `640x480-72'
Setting video mode to `/dev/fb0'
$

There are also no messages in /var/log/kern.log about this, either.

Why does the resolution change not happen?

NOTE: The rest of the framebuffer functionality works just fine. I can directly write pixels to it, which show up on screen. But the resolution is stuck at 1024x768-75. Running fbset as root doesn't help either.

During boot time, the kernel says:

[    0.360247] efifb: probing for efifb
[    0.360262] efifb: No BGRT, not showing boot graphics
[    0.360264] efifb: framebuffer at 0xb0000000, using 3072k, total 3072k
[    0.360266] efifb: mode is 1024x768x32, linelength=4096, pages=1
[    0.360268] efifb: scrolling: redraw
[    0.360269] efifb: Truecolor: size=8:8:8:8, shift=24:16:8:0
[    0.360330] Console: switching to colour frame buffer device 128x48
[    0.361439] fb0: EFI VGA frame buffer device

The framebuffer is EFI:

Frame buffer device information:
    Name        : EFI VGA
    Address     : 0xb0000000
    Size        : 3145728
    Type        : PACKED PIXELS
    Visual      : TRUECOLOR
    XPanStep    : 0
    YPanStep    : 0
    YWrapStep   : 0
    LineLength  : 4096
    Accelerator : No

OS: Ubuntu 21.10

Kernel: 5.13.0-28-generic

GPU: RTX 3070

CPU: Xeon W-2140B

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