Bug 66697

This sounds very much like an X server bug. You may want to provide information
about your video hardware.

Display hardware is Matrox G450

Processor is dual SMP:  i686 Pentium II (Deschutes) @ 450 MHz

X is XFree86-4.2.0-50.16

Problem seems to be triggered by something in Nautilus only.  Problem
occurs both with icons on desktop and with icons in nautilus window.

Tentatively, I'm no longer seeing this problem on
rawhide-release-20020706-1
Any idea what fixed it?

Bad news, its not completely fixed, although it does seem to be much better.

I'll play with it some more to see if I can find a way to reliably reproduce the
problem.

I can create the detritus quite reliably by opening xosview on screen0 of 
the dual head display, then grabbing a gnome-terminal window and moving it 
around the screen, and in particular movie it so that it obscures
and reexposes the nautilus desktop icons.

There is continuous activity on xosview, so my guess is thats its related to 
upadates in multiple windows at the same time.

The detritus is usually the icon labels rendered in black at random positions
over the screen, but I've also seen other text droppings, not all of them from
nautilus.

This is all with today's rawhide updates:
rawhide-release-20020709-1
XFree86-4.2.0-52.01

This almost certainly is either a bug in the Matrox driver's 2D acceleration
code, or the hardware mouse pointer code.

Can you try using Option "swcursor" in your X config, and report back if
the problem goes away.  If not, try Option "noaccel" instead.  Then try
both of them at once.  Report back what if anything makes the problem
go away, and we can then work on pinpointing where the corruption occurs.

Option "swcursor"                no fix.
Option "noaccel"                  fixed.
Option "noaccel" and :swcursor"   fixed. 

I played with the Xaa options.....

Option "XaaNoScreenToScreenCopy" by itself, just on Screen-0, fixed the problem.

Should I be taking up this problem with Matrox at this point?

Created attachment 67224 [details]
fixed version of /etc/XF86Config-4

Yes, this problem should be brought to the attention of Matrox if
possible.  They maintain the mga driver for the most part now.  The
specs are not available for the G450, however it might still be able
to debug/troubleshoot the problem and fix it.

For now, I've added the above option to the G450 configuration by
default until a proper fix can be found.

The latest hwdata package in rawhide has this change now.  hwdata-0.37-1

Reopening bug, to track for real fix rather than workaround above.

This problem has gotten much worse with XFree86-4.2.99.2-0.20021110.3 from
rawhide.   Now the transparent cursor is left splatted all over Screen-1.
This is the other screen from the first problem and the new splats are not fixed
by 'Option      "XaaNoScreenToScreenCopy" ""'

In order to try and find the best fix, I will need you to test-drive
some different drivers for me.

ftp://people.redhat.com/mharris/test-drivers/mga_drv.o

Please copy this overtop of the existing mga_drv.o that comes with
the rawhide XFree86 you're using now.

Edit the config file, and comment out all XaaNo options, noaccel, etc.

We want to test this driver with no special options enabled.

Please provide me with an updated comment, as well as the output of:
ls -al /usr/X11R6/lib/modules/drivers/mga_drv.o

and a new copy of your X log and config file

Created attachment 86424 [details]
/etc/X11/XF86Config

Created attachment 86425 [details]
/var/log/XFree86.0.log

Looks good so far.   I've not seen any text detritus nor cursor splats
after about 1 hour of usage.

ellson@amber:ellson> ls -al /usr/X11R6/lib/modules/drivers/mga_drv.o
-rw-r--r--    1 root     root       189974 Nov 25 19:32
/usr/X11R6/lib/modules/drivers/mga_drv.o

Great, closing as fixed in rawhide with Xrender patch