[SGVLUG] video problems (was: unstable ubuntu system)

David Lawyer dave at lafn.org
Sun Feb 24 09:21:39 PST 2008


On Sat, Feb 23, 2008 at 05:02:13AM +0000, bobjaffray at juno.com wrote:
> BJ: Excuse commenting at the beginning of the post.
> I find that on installing Ubuntu 7.10 on a my older laptop
> it doesn't configure the video and ends up with a blank screen.
> That laptop has only 256MB of RAM.
>  
> Bob Jaffray
Well, I operate with 48MB of RAM (only 20% of the RAM mentioned above
and video works fine).  I can even play movies (if I permit frames to
be dropped).  Even though there is a framebuffer module for my video
card the documentation on it only gives the technical specs such as:
--------------------------------------------------------------------------
	*  8 bpp pseudocolor mode (with 18bit palette)

There are two 4 bpp modes. First mode (selected if nonstd == 0) is mode with
packed pixels, high nibble first. Second mode (selected if nonstd == 1) is mode
with interleaved planes (1 byte interleave), MSB first. Both modes support
8bit wide fonts only (driver limitation).
---------------------------------------------------------------------------
Nothing is said about how to install the module.  I've listed the
module in /etc/modules so that it will load.  Turns out there are all
sorts of "driver limitations": the driver fails to support features in
the module.  The driver doesn't support acceleration even though the
video card does.  Also, will the typical desktop user understand this
documentation: How many know about bpp, high nibbles, MSB, or
pseudocolor?

A major problem with what I've done is that the video driver gets
installed about half way thru the boot process.  The screen flashes
and all the dmesg's (boot-time messages) prior to this video transition 
get lost.  So the video driver should be installed at the beginning of
the boot process, perhaps by giving it as a kernel-parameter (look up
the file by this name in the kernel documentation).  You use lilo or
grub to give the parameter to the kernel.  I think it's video=....
I intend to try this.

The above shows why Linux has trouble gaining market share on the
desktop.  You may need to be a guru in order to get it working and
even then, various limitations in the Linux software may result in
hardware not functioning at full capabilities.

Regarding the laptop.  Will not it boot in text mode?  I would expect
that text on the screen can be obtained without any video driver.  If
there isn't any way to tell Ubuntu to boot in text mode (or a version
of Ubuntu that does this) you could always try another distribution
like Debian.  I really doubt if more memory will solve this problem
and think it's a problem of the video driver not being found or
loaded.  Of course it might also be a hardware problem.
[snip]
			David Lawyer


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