ports/116851: x11-drivers/xf86-video-mga - Xorg 7.3 mga driver fails to read video BIOS (G450 dual-VGA)

Warren Block wblock at wonkity.com
Tue Oct 23 16:17:53 PDT 2007

On Tue, 23 Oct 2007, Kevin Oberman wrote:
> I installed your patch and I no longer get errors in the Xorg.0.log
> file, but I still have problems.
> I now have two displays, but the right display only runs at 1024x768
> with the left runs at 1280x1024.

What should it be?

The Position option in each monitor is supposed to define which part of 
the big virtual bitmap that monitor displays.  But it depends on the 
size of the virtual bitmap and the resolution of the monitors.

You can also change things live by running xrandr interactively:

xrandr --output VGA2 --left-of VGA1

or something like that.  I haven't experimented with it much.

There's also a PreferredMode option for the Monitor section which might 

Option "PreferredMode"  "1280x1024"

> If I try swapping the "Position" lines between monitor 0 and 1, I go
> back to the old mirror effect, with the right screen still at 1024x768.

> I get the following messages on my vty:
> WB: Reading 128K from /dev/mem address 0xc0000

Okay, that's good.

> info: [drm] Initialized card for AGP DMA
> drm0: [ITHREAD]
> [config/hal] couldn't initialise context: (null) ((null))
> SESSION_MANAGER=local/pak.es.net:/tmp/.ICE-unix/98465

That's odd, and new to me.  However, I use xdm and Xfce, so maybe it has 
to do with something else.  Maybe a securelevel or hal configuration 
difference?  No config/hal or SESSION_MANAGER in my log.

> The only warning in the log is:
> (WW) OS did not count PCI devices, guessing wildly
> (WW) MGA(0): Option "Position" is not used
> I don't like the look of the latter error.

No, I see both of those messages in mine, too.  (I only noticed the 
"not used" warning today.  Maybe it's talking about the 0 0 as 

> Any ideas? I did edit the "Monitor" sections and tried both with
> explicit sync rates and commenting them out and using DCC. Made no
> difference. I must admit that I am baffled.

You can make monitor entries in the Device section to set default 
positions.  Sorry, haven't really tried that, either (well, I tried it a 
couple of weeks ago on my T42 notebook with a Radeon--did not go well, 
locked up, but needs to be tried again).

> Also, is xinerama no longer usable with the 7.3 and the G450? Or so you
> just prefer randr? (I can see that randr has advantages.)

I did have one person have problems trying to use both (without further 
details given).

Xinerama is now automatically loaded, but I have plenty of questions 
about it myself.  For instance, what happens if you have a dual-head 
G450 and add a PCI card for a third monitor--can they all be part of the 
same desktop?

I borrowed some PCI cards yesterday, so maybe I'll be able to answer 

-Warren Block * Rapid City, South Dakota USA

More information about the freebsd-x11 mailing list