Hi!
The same problem in xserver-xfree86 Debian package version 4.3.0.dfsg.1-1
Applying the attached patch solves the problem, this patch already have
the current XFree86 mainstream.
http://cvsweb.xfree86.org/cvsweb/xc/programs/Xserver/hw/xfree86/drivers/s3/s3_accel.c?rev=1.3&content-type=text/vnd.viewcvs-markup
See the file xc/programs/Xserver/hw/xfree86/xaa/XAA.HOWTO Section 2.3
(Solid Lines), void SubsequentSolidBresenhamLine(...)
The file is also accessible at
http://cvsweb.xfree86.org/cvsweb/xc/programs/Xserver/hw/xfree86/xaa/XAA.HOWTO?rev=1.13&content-type=text/vnd.viewcvs-markup
NMarci
P.S.: I have tested the "almost horizontal line" code with the hardware
0000:00:0b.0 VGA compatible controller: S3 Inc. 86c764/765 [Trio32/64/64V+]
(rev 54)
--- xc/programs/Xserver/hw/xfree86/drivers/s3/s3_accel.c.orig 2001-10-28
04:33:44.000000000 +0100
+++ xc/programs/Xserver/hw/xfree86/drivers/s3/s3_accel.c 2004-06-05
18:44:02.000000000 +0200
@@ -310,7 +310,7 @@
int error, e1, e2;
error = minor + err;
- e1 = major;
+ e1 = minor;
e2 = minor - major;
if (major) {
