Re: [gentoo-user] Kernel setting for frame buffer (2.6.23-r5)

[Etaoin Shrdlu <shrdlu@unlimitedmail.org>]

On Wednesday 9 January 2008, reader@newsguy.com wrote:

> For a good while now I've had a setting like this in grub.conf:
>
> (wrapped for mail)
> kernel /kernel-2.6.23-r5 root=/dev/hda5 \
>       vga=0x31A video=vesafb:mtrr,ywrap
>
> I'm not sure any more how much of that is necessary.

FWIW, I have only the vga= part (more exactly, I have vga=791, with the 
argument in decimal. Yours would be vga=794, but the base is just a 
matter of habit).

> I have it there to allow console mode to have much larger resolution
> than default (The appearance is much smaller text)
>
> I think this setting in kernel config is the one needed for that:
>    CONFIG_FB_VESA=y

Correct.

>
> But I'm trying to build a pared down kernel a console only setup.
> Going thru the kernel settings in menuconfig... I'm not finding the
> one that creates that `CONFIG_FB_VESA=y' element.

During make menuconfig, hit / and enter the text you want to search for 
(in this case, obviously, it's FB_VESA), and hit enter. It should show 
you where that particular option is found in the configration. In my 
case (vanilla 2.6.23.9), it shows

Symbol: FB_VESA [=y]                                                                                                                                   
Prompt: VESA VGA graphics support                                                                                                                  
  Defined at drivers/video/Kconfig:595
  Depends on: HAS_IOMEM && FB=y && X86
  Location:                                                                                                                                           
    -> Device Drivers
      -> Graphics support
        -> Support for frame buffer devices (FB [=y])
  Selects: FB_CFB_FILLRECT && FB_CFB_COPYAREA && FB_CFB_IMAGEBLIT && 
VIDEO_SELECT                                                                   

Notice the "Location:" bit.

> I've gone back and forth through the setting under:
> Device drivers/Graphics-support .. checking Support for FrameBuffer
> devices (both as module and builtin in different saves).

It should be there. Which kernel sources and release are you using?
Also note, in the above output, that VESA_FB depends on HAS_IOMEM and FB. 
If you don't select either, the VESA_FB option will not be shown.
Since you obviously have FB set (otherwise you would not see the 
Userspace VESA option), you can check the status of HAS_IOMEM. With the 
same / trick described above, search for HAS_IOMEM. It does not give you 
a lot of information this time, but at least it should tell you whether 
the option is enabled. In my case, it just says

Symbol: HAS_IOMEM [=y]

In case you don't have it active (very strange, since it should be part 
of the default configuration and not modifiable), try a "make mrproper" 
and start over with make menuconfig, which should start with the default 
config this time.

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