The old pentium that I have resurrected as an X-terminal has an S3 Trio64
video card.  My early experience with that X-terminal and either KDE-2.2.2
or KDE-3.0.1 was fine but top showed there was a severe memory leak for the
XF86_S3 server with XFree86-3.3.6 growing to 30-40MB in sometimes less than
an hour.  This version of XFree86 is no longer supported so I was happy to
recently try XFree86-4.2.0 which finally brings support of the S3 Trio64
video card to the 4.x series.  I used the pre-compiled binaries from
ftp://ftp.xfree86.org/pub/XFree86/4.2.0/binaries/Linux-ix86-glibc22
appropriate to my Linux (Debian woody) system, not the experimental deb
packages that apparently are available elsewhere.

The good news is there is no memory leak problem.  Top shows X rarely goes
above 13MB with the S3 driver and XFree86-4.2.0 and heavy use with either
KDE2.2.2 or 3.0.1. I am extremely grateful for that.  Nevertheless, there
are some other problems with the S3 Trio64 driver support under
XFree86-4.2.0 that I ran into and had to work around. I would like to
mention those problems here in the hope that my workarounds will be useful
for others.  Of course, I also look forward to the day when the workarounds
will not be necessary!  My system is a pentium-133 X-terminal running
kernel 2.4.18 and XFree86-4.2.0 (whose details were given above).  All my
xclients (such as those from the KDE-3.0.1 desktop) run on my faster box
(Athlon-600) and merely display results on the slower X-terminal pentium-133
which runs the X server.

(1) S3 Documentation.  There is none I can find.  No README.S3 no man page,
etc.  I checked all the locations where the S3-virge documentation shows up,
and there is nothing about the S3 driver.  I have no workaround for this
problem except to be quite conservative about what I try in the XF86Config-4
file.

(2) xf86config claims S3 not supported.  However,
/usr/X11R6/lib/modules/drivers/s3_drv.o does exist so I worked around this
problem by replacing the 'Driver "vga"' line that xf86config produced with
'Driver "s3"'.

(3) A trusty home-built modeline for 916x687@85Hz that I have used for years
for this combination of video card (S3 trio64) and monitor (Sony Multiscan
15sfII) and also recently for XFree86-3.3.6 failed to work under
XFree86-4.2.0. /var/log/XFree86.0.log shows the modeline parameters are
being parsed properly, but the resulting display seems scrambled in a way
that suggests horizontal synch is not working.  I think it is pretty clear
that the new S3 driver is not producing the same timing results as the old
S3 driver for the same mode line. To work around this I tried everything
with horizontal synch including +hsync and -hsync as well as changing the
placement and duration of the hsynch.  I did find that xvidtune would switch
from 800x600 to 916x687 without problems, but I could not start X with
916x687.  My workaround was to drop to the lower standard resolution of
800x600@85Hz. (1024x768@85Hz is not available to me because of the
horizontal frequency limit on my monitor, and the flicker from 1024x768@75Hz
[which also worked] noticably strained my eyes.)

(4) Another problem is anti-aliasing doesn't work.  I am getting the message
from /var/log/XFree86.0.log "(II) Initializing built-in extension RENDER"
with no subsequent error message, but xdpyinfo does not mention RENDER so I
presume it is not currently supported by the new S3 driver.  Count this as a
wishlist bug report to get RENDER working for the new S3 driver.  KDE 3.0.1
is very nice with AA on my fast box, and I would like to see the same
effects on my X-terminal.

(5) All the above I can live with, but this complaint is much more serious.
If I use ctrl-Alt-FN to get to a virtual terminal, then alt-F7 to get back
into X, the whole X system goes crazy and starts sending bad frequencies to
my monitor.  Such problems never occurred with XFree86-3.3.6.  For 4.2.0,
800x600*85Hz works fine initially, but after the above sequence the
resulting screen is shifted by 90 per cent of the width (i.e., only 10 per
cent showing.) 1024x768@75Hz works fine initially, but after the above
sequence I get a "out of range" message from my monitor (which I presume
means it was trying 1024x768@85Hz [or whatever] that goes beyond my
monitor's frequency limit without paying any attention to the frequency
limits I put into XF86Config-4).  I have temporarily worked around this
problem by disabling the ctrl-Alt-FN sequence so I don't use it by accident
out of habit.  But obviously this bug should be a high priority since it may
put some old monitors at risk that don't have the hardware protection
against out of range frequencies that my monitor proved to have.  This was
the first time in 6 years Linux experience that I had ever run that monitor
out of range, and I hope not to repeat the experience....;-)

To sum up, I am going to continue to use the new S3 driver because it seems
to solve the memory leak plaguing the old 3.3.6-based S3 driver, and I am
willing to live with the above workarounds for now, but I hope the new S3
driver gets some on-going effort to correct these deficiencies.  I expect a
second surge of interest in that driver as more people convert their low-end
pentiums (where the S3 Trio64 video card was extremely popular) to
X-terminals.  Sorry my programming skills are not up to helping out directly
with the S3 driver effort, but I am certainly willing to help with bug
reports.  If some of the problems mentioned above are difficult to verify,
then by all means get back to me (off list since I am not subscribed), and I
would be willing to try any experiments to help sort out these problems.

Alan W. Irwin

email: [EMAIL PROTECTED]
phone: 250-727-2902     FAX: 250-721-7715
snail-mail:
Dr. Alan W. Irwin
Department of Physics and Astronomy,
University of Victoria, P.O. Box 3055,
Victoria, British Columbia, Canada, V8W 3P6
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