Fwd: [Voyage-linux] Howto get Framebuffer working

Sat Oct 25 16:03:45 HKT 2008

I believe punky intended this exchange to go to the list, but the list
dropped off the recipients list. Probably my fault.

Note the link to the experimental kernel.

If you try it, make sure to put a framebuffer driver (eg lxfb) in
/etc/modules before rebooting, or do it with SSH afterwards. Otherwise
you'll end up with a blank screen on the 3C3. If anyone has any other
board they can test on it would be useful, because there should be a
VESA framebuffer driver in there already, but maybe the ALIX doesn't
implement VESA.

---------- Forwarded message ----------
From: Richard Urwin <soronlin.voyage at googlemail.com>
Date: Fri, Oct 24, 2008 at 10:58 AM
Subject: Re: [Voyage-linux] Howto get Framebuffer working
To: Kim-man 'Punky' TSE <punkytse at punknix.com>

I can think of three possibilities:

1. Set the mode on the boot line.

2. Maybe the ALIX doesn't like VESA. Its BIOS is pretty poor; it can
not boot from USB for example. Maybe try
CONFIG_FB_VGA16=y
CONFIG_FB_VESA=m

3. Allow for the framebuffer, but don't use it until it's added by the user.
CONFIG_FRAMEBUFFER_CONSOLE=m
CONFIG_FRAMEBUFFER_CONSOLE_ROTATION=y
CONFIG_FB_VGA16=m
CONFIG_FB_VESA=m

I shall try (1) at the weekend.

Last night I had pictures on the screen at 1280x1024 and 32bpp.
Mplayer works too.

On Fri, Oct 24, 2008 at 5:04 AM, Kim-man 'Punky' TSE
<punkytse at punknix.com> wrote:
> Hi Richard,
>
> I followed Debian and here is what they built:
>
> CONFIG_FRAMEBUFFER_CONSOLE=y
> CONFIG_FRAMEBUFFER_CONSOLE_ROTATION=y
> CONFIG_FB_VGA16=m
> CONFIG_FB_VESA=y
>
> I am still unsure what is needed to make proper framebuffer driver loaded
> and started at boot.
> Regards,
> Punky
>
>
> Richard Urwin wrote:
>>
>> Thanks for that.
>>
>> I now have a framebuffer, and a usable system. (I only seem to have
>> 640x480, but I don't think that affects us right now.)
>>
>> There is a problem though. As soon as the second OS start-up happens
>> (the first unpacks the second?) the screen stops updating. Loading a
>> fb driver - either vga16fb or lxfb - it then displays the screen. It
>> seems that, contrary to how I read the fbcon documentation, fbcon is
>> assuming that a framebuffer exists, and not defaulting to the system
>> console.
>>
>> This is good enough for me, but probably not how you want 0.6 to go out.
>>
>> Putting vga16fb in /etc/modules would be a partial fix, but there is a
>> long period during boot when you can't see what is happening.
>>
>> The best I can suggest is to build fbcon as a module, and to put fbcon
>> and vga16fb in /etc/modules in that order.
>>
>> ALIX owners can then swap vga16fb for lxfb.
>>
>> If you want to produce a test version of this, or something else, I
>> can test it, although it might not be before the weekend.
>>
>> On Thu, Oct 23, 2008 at 4:26 PM, Punky Tse <punkytse at punknix.com> wrote:
>>
>>>
>>> Hi all,
>>>
>>> Just build a new kernel with more FB driver support:
>>>
>>>
>>> http://www.voyage.hk/dists/experimental/linux/linux-image-2.6.26-486-voyage_6.0-1_i386.deb
>>>
>>> This should have CONFIG_FRAMEBUFFER_CONSOLE enabled.  Please test and let
>>> me
>>> know the result.
>>>
>>> Regards,
>>> Punky
>>>
>>>
>>> Richard Urwin wrote:
>>>
>>>>
>>>> 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
>>>> <mailto: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
>>>>
>>>
>>>
>
>
> --
> Regards,
> Punky
>
> Voyage Solutions (http://solution.voyage.hk)
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>

-- 
Richard