set number of lines in framebuffer console

LEXUSRS · 01-31-2020, 05:04 AM

Hi all,
i have some problems in understanding framebuffer conlose settings...
i created some kernel with kernel mode setting (DRM and framebuffer console support) and add video=640x480 option on boot...
when drm deactivaling vga console(80x25) and load framebuffer device driver, console switching to colour frame buffer device 80x30
how can i set 25 lines, instead of 30
no X-server used, so xrandr and resize don't work
stty set 25 lines, but it just cut 5 lines from bottom of the screen
how can i get 25 lines in console on actual screen size?
ps. sorry for bad english

business_kid · 01-31-2020, 05:26 AM

Changing font size is the lazy way.

Terminus fonts go up to 32pt, although that may not work well on all systems. That gives 32 lines, and you should settle for that.

OTOH, setting a font like cp850-8x8 gives zillions of lines.

allend · 01-31-2020, 05:51 AM

Welcome to LQ!
Have you tried using 'fbset'?

LEXUSRS · 01-31-2020, 06:11 AM

Quote:

Originally Posted by business_kid

Changing font size is the lazy way.

font size aslo change visible number of columns, so it isn't my way

Quote:

Originally Posted by allend

Welcome to LQ!
Have you tried using 'fbset'?

thx, fbset is not affected when kernel param "video=" is set
if this param isn't set kernel loading in my monitor recommended resolution (read edid), and then fbset resize console window to any mode (800x600,1024x178,1600x1200 and etc.), but he cut window size to that param, resolution is not changing...

allend · 01-31-2020, 07:13 AM

It might help to know some more about your system. Please post the output of 'fbset -i' and 'ls /sys/class/drm'.

LEXUSRS · 01-31-2020, 09:14 AM

Quote:

Originally Posted by allend

It might help to know some more about your system. Please post the output of 'fbset -i' and 'ls /sys/class/drm'.

it's a pxe-boot system, on 5.5 kernel and root-dir based on centos5

dbset output:

Code:

mode "640x480"
    geometry 640 480 640 480 32
    timings 0 0 0 0 0 0 0
    accel true
    rgba 8/16,8/8,8/0,0/0
endmode

Frame buffer device information:
    Name        : i915drmfb
    Address     : (nil)
    Size        : 1228800
    Type        : PACKED PIXELS
    Visual      : TRUECOLOR
    XPanStep    : 1
    YPanStep    : 1
    YWrapStep   : 0
    LineLength  : 2560
    Accelerator : No

"sys" dir is empty, kernel build w\o sysfs support

allend · 01-31-2020, 09:59 AM

Quote:

Name : i915drmfb

Intel graphics.
The output of 'ls /sys/class/drm' would given the names of the graphic outputs on your system.

I am writing from a laptop that I usually use with an external 1920x1080 monitor. I use a kernel append 'video=LVDS-1:d video=VGA-1:1920x1080@60e" ' on this machine (also with Intel graphics) that disables the laptop internal screen (LVDS-1) and enables the external monitor (VGA-1) at boot. The details for that append can be found in modedb.rst in the kerenl documentation.

LEXUSRS · 02-03-2020, 12:27 AM

Quote:

Originally Posted by allend

Intel graphics.
The output of 'ls /sys/class/drm' would given the names of the graphic outputs on your system.

I am writing from a laptop that I usually use with an external 1920x1080 monitor. I use a kernel append 'video=LVDS-1:d video=VGA-1:1920x1080@60e" ' on this machine (also with Intel graphics) that disables the laptop internal screen (LVDS-1) and enables the external monitor (VGA-1) at boot. The details for that append can be found in modedb.rst in the kerenl documentation.

rebuild kernel with sysfs support

Code:

ls /sys/class/drm
card0  card0-DP-1  card0-HDMI-A-1  card0-VGA-1  renderD128  ttm  version

kernel boot parm is "video=card0-VGA-1:640x480", all documentation about modedb, framebuffer and other i read many times...
any my attempt to set LINES=25 is not affected to framebuffer console...

ehartman · 02-03-2020, 01:01 PM

Quote:

Originally Posted by LEXUSRS

kernel boot parm is "video=card0-VGA-1:640x480",

As 480 / 25 is 19, you would need a 9x19 (pixels) font in the framebuffer.
The standard VGA mode for the console uses a 9x16 one, and thus is the "30 lines" mode of the console in this resolution
I believe a real VGA adaptor used 640x400 for its text mode, 640x480 was only used in graphical ones.

pan64 · 02-03-2020, 01:42 PM

if I remember well: the resolution is given, so you can only play with the [size of the] font. You can only use the full screen, I have never heard about virtual display/desktop or similar when you use a simple console.
Return back to the original question: you need pick a valid resolution and find an appropriate font...

business_kid · 02-03-2020, 02:24 PM

@pan64: I gave the OP that back in post #2, Terminus 32pt font giving 27 lines but he didn't want it