On powerpc I get drawing errors for lines and rects (maybe also others). What happens is, that eg. a line drawn from eg. point (-1, 0) to (-1, 20) will be partially visible. This seems to only happen on server side pixmaps and windows that are at the far left side of the screen. (I am not using the composite extension)
Created attachment 4722 [details] small xlib program that reproduces the error To reproduce the error, start the program and move it to the left out of the screen. Make sure it is exactly at the left of the screen, and then force an expose for the window (either by moving another window over it, or moving the window 1 pixel out of the screen and back again)
Created attachment 4723 [details] screenshot of the test
This could be driver specific rather than architecture specific; does it also occur with Option "NoAccel" or the fbdev driver?
Setting NoAccel does not help. Scrolling and moving windows is dog slow now, but the bug persists. The same problem also exists inside the Xvfb server.
And it doesn't happen on other architectures?
I am not able to reproduce this on i386 (xorg 6.9.0, debian). On ppc I am able to reproduce the error with both xorg 6.8.2 (debian package) and 7.0rc4 (build with jhbuild).
Sorry about the phenomenal bug spam, guys. Adding xorg-team@ to the QA contact so bugs don't get lost in future.
Hm, two years since the last activity and the problem still exists with Xorg version 7.3 (1.4.0.90). So, some more information: 1. The line is drawn as if it goes from -1,0 to 0,100 in my test 2. A line from -2,100 to -1,0 does not expose the bug 3. A line from -1,100 to -2,0 does expose the bug (looks like a line from 0,100 to -2,0) If there is anything I can do to help, I'll try to do my best. I have tried to look a bit at fbbits.h, etc. but unfortunately I don't know my way around that code, and I don't even know if it is used in this case.
Does compiling the X server with -fsigned-char work around the problem?
I just rebuild the debian xorg-server and libx11 packages with -fsigned-char, but doing that does not have any effect. (Though it is true that char defaults to be unsigned on this machine.)
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