[blfs-support] /dev/fb0 not being created on boot

Ken Moffat zarniwhoop at ntlworld.com
Fri Nov 22 12:25:08 PST 2013

On Fri, Nov 22, 2013 at 07:05:14PM +0000, Richard Melville wrote:
> Ken, I'm using vesafb on a web server with no Xorg, and I just use the
> console.  I realise that my kernel was quite old but as I like to check
> every configuration option (often because of new hardware) it takes a long
> time to configure a new kernel and becomes incredibly boring towards the
> end :-(  Therefore, I usually limit my upgrades to about one per year, or
> when I can be bothered.

 OK, but in that case I suggest that you go for "early stable"
kernels (.1, .2, etc).  You said you had been using 3.7-rc8 - that
probably turned out to be totally good for your uses, but sometimes
even .0 releases still have issues in a few places.

 Also, the config you use in a late -rc will normally not provide any
extra questions for released / stable kernels in the same series if
you use 'make oldconfig'.
> Bruce, my framebuffer config was much like yours but with one exception: I
> had CONFIG_X86_SYSFB=y.  This was stopping vesafb loading and stopping
> /dev/fb0 being created.  I've removed that option, reconfigured, and now it
> all works as expected.

 Interesting.  That option works ok on intel (I'm running with it at
the moment), I'll try to remember that for the future - my server
also runs with CONFIG_FB_VESA and vga=792 (it's a radeon RS780, when
I got it I had no experience with modern ATI hardware and totally
failed to get the radeon framebuffer to work - 80x25 is too
restrictive for me!) - for the moment I'm running 3.10 (LTS) there.
> Regarding vga=792, that still works for me.  If I substitute video=1024x768
> the command is ignored an I get a large, ugly font.  I'm currently using
> grub-2.0, so I can't understand what the problem is likely to be.  Any
> ideas?
> Richard

 Stick with vga=792 since it still works ?  Any idea how large the
font is, or how many pixels in the screen size when you boot with
video=1024x768 ?

 When the box boots, you get the font from its bios.  But when the
LFS bootscripts start to run it ought to switch to your specified
font (provided the setup supports it, e.g. my own 12x22 is only
supported on framebuffers and I've not tried it with Vesa, my screen
there is physically 1024x768 so I use an 8x16 font on that).

 So, basically work out what sort of console font *size* will suit
you, then try "setfont" in a spare tty and see if any of the
available fonts look ok _and_ provide the character coverage you

 My own LatGrkCyr are intended for white/pale text on a black
background and I'm told that at least one of them looks awful with
dark text on a pale background : there is a balance between getting
adequate coverage, shapes which do not offend our own particular
sensibilities, and being able to distinguish the various accents and
diacritical markings - for some uses, noting that a glyph is e.g.
"letter a with accent" may be good enough, but others may wish to be
able to see at a glance what sort of accent is present, particularly
in unfamiliar languages.

das eine Mal als Tragödie, dieses Mal als Farce

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