Re: Weird problem with a G400 - shows only junk through mga_vid

On Tue, Oct 11, 2005 at 09:49:39AM +0200, Attila Kinali wrote:
> On Mon, 10 Oct 2005 21:31:16 +0300
> Mikko Nahkola <[email protected]> wrote:
> 
> > > Ie, could you try to run -vo mga from the console without
> > > X running ?
> > 
> > I did. Didn't I send the screenshot already? I took one from that too. 
> > No luck. ... Hm. Ok, seems I didn't send this yet. Attaching now.
> 
> Ok,.. now that's getting strange.
> 
> > > BTW: which X server are you using ?
> > 
> > X.org 6.8.2, I think the thing has some Gentoo-specific patches.
> 
> I run here a xfree86 4.3 from debian, but i slowly start to doubt
> that this is the problem. 

Especially as it refuses to work (and more consistently too) without 
running X as well.
 
> > The funny thing is that it occasionally does draw the right image, but 
> > only when running X and at least _starting_ with some additional load. 
> > ("nice emerge -update -deep world & mplayer", heh...)
> 
> Ok, this is now really getting strange. I cannot think of a
> problem, beside memory management that would cause a behaviour like
> this.

I've gotten it to display the right image since then with less load. 
After upgrading to a more-patched version of X server.

> Hmm.. maybe, the card you have is not able to cope with the full
> memory range of the pc. But that would be very strange too,
> as the time of 16MB limited devices is long over.

Is the AGP aperture definition in any way relevant? The motherboard is a 
bit weird there. Oh, and it _does_ have some memory limits.

Oh, and matroxfb works about half the time, the other half it does the 
same as mga_vid ... nasty. Wonder why X works every time (so far...)

> I have to think about a system to test that.
> But that will take a while as i'm quite busy these days :(
> 
> At least the screenshot you send suggest that the memory
> region coppied to the card is something generated as it
> shows a very regular pattern. And if the log matches this
> screenshot, then the bars would be at a spacing of about 32 pixels
> (64bytes) which would also suggest that it's some datastructure.
> 
> BTW: does Xv work for you?
> It uses a very similar method to mga_vid thus should show
> the same behaviour.

I think I haven't gotten Xv to fail yet. I did get it to show badly 
distorted colors once, though.

> > I guess I'll rebuild the old thing as a Windows games box for the kids. 
> > Got a nice old "Pippi Långstrump" CD that needs something between 
> > Windows 3.0 and 98SE, for example. (Wine doesn't do _that_ old APIs anyway.)
> 
> NO! WAIT! I want that bug nailed down :)

I'd not be all that surprised if it were just a hardware quirk. I 
mean, this thing has more than its share of those already... back when I 
bought the system the vendor was having real problems with graphics card 
compatibility on these. And for a long time I had to hand-tweak the 
kernel sources to get anything like reasonable I/O performance...

Also, the graphics card is a second-hand find from a local PC shop's 
back room.


-- 
Mikko Nahkola <[email protected]>