[buug] Linux framebuffer console and fbset

Ian Zimmerman itz at speakeasy.org
Mon Jun 10 22:05:58 PDT 2002


Reading the documentation about the fbset command, I get the
impression that I ought to be able to change the text resolution or
timing parameters of my virtual terminals using it.  However, this
does not happen:

Script started on Mon Jun 10 21:59:04 2002
kronstadt:~# fbset

mode "1024x768-76"
    # D: 78.653 MHz, H: 59.949 kHz, V: 75.694 Hz
    geometry 1024 768 1024 768 8
    timings 12714 128 32 16 4 128 4
    rgba 6/0,6/0,6/0,0/0
endmode

kronstadt:~# fbset --verbose 1024x768-90
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 `1024x768-90'
Setting video mode to `/dev/fb0'
kronstadt:~# fbset

mode "1024x768-76"
    # D: 78.653 MHz, H: 59.949 kHz, V: 75.694 Hz
    geometry 1024 768 1024 768 8
    timings 12714 128 32 16 4 128 4
    rgba 6/0,6/0,6/0,0/0
endmode

kronstadt:~# 
Script done on Mon Jun 10 21:59:31 2002

Why? What am I doing wrong? All the ioctl calls succeed, I know that,
because I looked at the fbset source and it exits immediately with a
loud complaint if anything fails.

And the documentation, although not lacking in quantity, completely
fails to explain the link between /dev/fb* and /dev/tty*.  I assume
that /dev/fb0 is the one to change, but how do I know?  

-- 
Ian Zimmerman, Oakland, California, U.S.A.
GPG: 433BA087  9C0F 194F 203A 63F7 B1B8  6E5A 8CA3 27DB 433B A087
EngSoc adopts market economy: cheap is wasteful, efficient is expensive.




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