bug in new x11 video code

[mol-devel@lists.maconlinux.org]

On Sat, Jun 01, 2002 at 06:10:05PM +1000, Ben Stanley wrote:
> I've been using the new x11 video code in mol-0.9.63 for a little while 
> now, and I've noticed that it occasionally gets a few pixels misplaced 
> while updating a scan line.

This is because MOL calculates and a checksum in order to detect
modifications to the framebuffer. Sometimes the checksum is constant
even though the actual framebuffer line is unchanged.

On my machine, performing the checksum speeds up the xvideo
code quite a bit. However, I'm usually running on a B&W G3
with a PCI graphics card. The situation might be different 
on an AGPx4 system. 

I'd love to hear comparision with and without the checksumming code.
There is a molrc switch for this:

use_xchecksum:		yes

> On the other hand, the problem I used to have with runaway scrolling has 
> now disappeared. (My kernel sometimes misses the up key events, and if 
> this happened while I'm scrolling a window in mol-0.9.60 then it could 
> take a minute for mol to catch up with all the key events...) This is a 
> really big plus for me that this behaviour is gone.

I reduced some delays in the via-cuda code (through which keyboard
input goes). The delays work around the fact that the (buggy) Apple
driver assumes the hardware has a non-zero response time.

Cheers,

/Samuel