[Voyage-linux] Howto get Framebuffer working

[Richard Urwin]

Thanks for the info, both of you. I am still edging a little closer to
a solution, bit by bit.

On Thu, Oct 23, 2008 at 2:38 AM, Kim-man 'Punky' TSE
<punkytse at punknix.com> wrote:
>
> There had been reported problem on the framebuffer support in voyage.  But I am quite suere lxfb.ko should be included in 0.5.2 and lenny release.

lxfb.ko does exist in the 0.6 release, but when I try to use it, the
screen goes black. It appears that Linux does not know how to draw to
the framebuffer. It is still assuming that it has a character mode
screen. I see green dots that appear as Linux displays text.

I get the same thing (but much earlier in the boot) if I put a VGA=
parameter on the boot line.

It seems to me that the buffer drivers are working, but the kernel
does not know how to display text on them. It seems telling that
Rainer can get it working using the Knoppix kernel.

Thanks for rubbing my nose in the documentation - it means I found this:

http://lxr.linux.no/linux+v2.6.26.7/Documentation/fb/fbcon.txt

======================================
        The framebuffer console can be enabled by using your favorite kernel
configuration tool.  It is under Device Drivers->Graphics Support->Support for
framebuffer devices->Framebuffer Console Support. Select 'y' to compile
support statically, or 'm' for module support.  The module will be fbcon.

      In order for fbcon to activate, at least one framebuffer driver is
required, so choose from any of the numerous drivers available. For x86
systems, they almost universally have VGA cards, so vga16fb and vesafb will
always be available. However, using a chipset-specific driver will give you
more speed and features, such as the ability to change the video mode
dynamically.

      To display the penguin logo, choose any logo available in Logo
Configuration->Boot up logo.

      Also, you will need to select at least one compiled-in fonts, but if
you don't do anything, the kernel configuration tool will select one for you,
usually an 8x16 font.

GOTCHA: A common bug report is enabling the framebuffer without enabling the
framebuffer console.  Depending on the driver, you may get a blanked or
garbled display, but the system still boots to completion.  If you are
fortunate to have a driver that does not alter the graphics chip, then you
will still get a VGA console.
======================================

Which is, of course, the problem I am seeing. When I go to the Voyage
kernel config for 2.6.26 I find this:


======================================
#
# Console display driver support
#
CONFIG_VGA_CONSOLE=y
# CONFIG_VGACON_SOFT_SCROLLBACK is not set
CONFIG_VIDEO_SELECT=y
# CONFIG_MDA_CONSOLE is not set
CONFIG_DUMMY_CONSOLE=y
# CONFIG_FRAMEBUFFER_CONSOLE is not set
# CONFIG_LOGO is not set
======================================

As I said, I have yet to (successfully) build a kernel, but it does
seem cut and dried that that CONFIG_FRAMEBUFFER_CONSOLE should be set
to "m" (at least). That does need a new kernel, because we also need
the compiled-in font.

> Of course, I would want to get the framebuffer issue sorted out before 0.6.0 release.

That is great news. Let me know if there is anything I can do to help.

--
Richard