> Hi,
> 
> I upgrade my RiscPC from 1 to 2MB VRam. On the RiscOS side all is fine, but
> on the NetBSD side many screen modes only produce rubbish. Screen modes
> that still work are 640x384, 640x400, 640x480 and 1024x768. Screenmodes
> that don't work are 800x600 and 896x672. The strange resolutions are because
> I compiled my own kernel with own video modes, but all problems are also
> with other kernels from ftp.netbsd.org as far as the screen modes are
> existing.
> 
I have only tried 640x480 ,1024x768 and 1280x1024
> In one of the not working screen modes the characters look like:

> But in about the first left 50-100 pixels this scramblin happens only in
> about every second pixel line.
> 
I believe its something to do with the alignment of the video memory. I don't 
see why 2MB should be different to 1MB though. 


> Also in video modes that work the screen sometimes flickers.
> 
> So my question is: Why does all this happen? In RiscOS I have no problems
> with these screen modes. It seems that the VIDC is programmed in a wrong
> way which sometimes works, but not always. Perhaps it is only a timing
> problem, as the flickering that sometimes happens looks like the flickering
> caused by a too high pixel clock under RiscOS.
> 
It's probably all related to the general nastiness of the Risc PC console 
code. I suspect some bug fixes are possible but a rewrite is what is really 
needed.

> Another problem is that I could not get X running in 16M colours. 256 and
> 32K were no problem (if I used a working screen mode) but trying 16M simply
> crashed the whole machine.
> 
X11 only supports 32k 256 and 2 colour modes.

> Is there a possiblility to fix these problems? I would be really interested
> in it because otherwise I had to think about buying a cheap PC box.
> 
All of these problems are fixable by moving the RISC PC console to wscons 
(NetBSD's machine independent console code). Following on from this a new
X Server would be needed to work with the updated console. I believe that work 
has been started on this. If you have the time and ability I suspect an offer 
of help would not be turned down.

Mike