[ltp] Framebuffer virtual consoles on the T21 - finally!

[Markus Alt]

Hi folks,

after the discussion approx. a month ago it looked like I wouldn't get
this going on my T21. Being obstinate, I played around a little more and
finally it works now!

I've always had that messed up framebuffer VCs after switching between
LCD and external display (with "normal" VCs it was fine). After the last
thread on this list regarding that topic, I've found out that the effect
was somewhat related to my XF86Config file, as there was no problem when
booting into runlevel 3 - only after starting X.

So I first configured X also using the framebuffer. Result: No problem!
But this was only with 8 bit color depth (boot parameter vga=827 for
1400x1050x8). Thus I considered changing the FB XF86Config file to 16
bit, which of course required to boot with an appropriate boot parameter
for 1400x1050x16. Following the good old try-and-error approach [1], I
found out that vga=828 was what I needed.

While doing this, I though that these problems could perhaps be caused
by the fact that framebuffers VCs and X' resolution and color depth
don't match. And really - that's it! When I had tried this so far, I had
the following combinations for the framebuffer 
 - 1024x768x8
 - 1024x768x24
 - 1280x1024x8
 - 1280x1024x24
 - 1400x1050x8
with X always being at 1400x1050x16. Changed the boot parameter and the
XF86Config file to match and voila! The only question left now is: Why
haven't I thought of this much earlier ...? ;-)

Perhaps because this was never an issue on the TP 600X I had before the
T21. The reason is simple: The 600X had a 1024x768 display and the
framebuffer VCs were also always at that resolution. But now with the
T21, 1400x1050 appeared a little too large to me for a console, thus I
wanted to keep the 1024x768 - and this didn't work together with X at
1400x1050.

So finally I don't have exactly what I wanted, but at least I have a)
found out why it didn't work before (which gives me a good feeling), b)
a large virtual console (although I consider it to be a little *too*
large) and c) Tux watching me watching him at boot time! I guess I'm now
what you call a "lucky camper". ;-)

Markus

[1] I haven't found this documented anywhere for a resolution greater
than 1280x1024. If anybody knows where or could tell me how to determine
that value in another way, I would be thankful.

----- The Linux ThinkPad mailing list -----
The linux-thinkpad mailing list home page is at:
http://www.bm-soft.com/~bm/tp_mailing.html