Bug 1223 - libxf86config HorizSync / VertRefresh lines written commented by default, breaking default configurations
Summary: libxf86config HorizSync / VertRefresh lines written commented by default, bre...
Status: CLOSED WONTFIX
Alias: None
Product: xorg
Classification: Unclassified
Component: Lib/other (show other bugs)
Version: git
Hardware: All All
: high normal
Assignee: Xorg Project Team
QA Contact:
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Blocks:
 
Reported: 2004-08-28 12:08 UTC by Mike A. Harris
Modified: 2011-10-15 15:33 UTC (History)
1 user (show)

See Also:
i915 platform:
i915 features:


Attachments
xorg-x11-6.7.0-libxf86config-monitor-freq-fix.patch (2.35 KB, patch)
2004-08-28 12:09 UTC, Mike A. Harris
mharris: 6.8-branch?
Details | Splinter Review

Description Mike A. Harris 2004-08-28 12:08:08 UTC
XFree86.org changed libxf86config to write out the HorizSync and VertRefresh
lines to the config file commented out by default.  I believe they made this
change due to the autoconfig stuff, with the mindframe that the horiz and
vert ranges could be autodetected via DDC probing now.

There are multiple problems with this.  Firstly, every time a config file
is re-edited using a tool that uses this library, it causes the existing
commented out entries to be treated like any comment, and new commented
out Horiz/Vert lines to be added again.  Over time, this causes the
config file to have many many commented out Horiz/Vert lines, which just
looks messy.  If the user actually changes monitors, the commented out
lines may differ in frequency and it wouldn't be clear which is correct
for their monitor in any case.  The person could end up using incorrect
frequencies if they were to uncomment the wrong ones.

Personally however, I think adding the lines uncommented at all is wrong
period.  Either the X server can always know the monitor frequencies 100%
of the time, or it can't.  If it can, then there's no need to write out
the lines for the user to be able to easily uncomment them.  If there is
any chance that "auto probe" of monitor wont work, then the default should
not be to comment out these lines.

While most modern displays do handle DDC, there are many scenarios where
DDC probing does not work.  It is just not reasonable to expect that DDC
will work "by default" on most systems, and making commented out horiz/vert
frequencies the default, with no way to override it, forces the user to
have to hand edit the config file always.  As such, OS vendor supplied
tools that use libxf86config as the underlying config file parser library,
must modify the library to not comment these lines out, in order to generate
config files that will work for all users regardless of wether DDC probing
works or not.

Please revert this XFree86.org change to libxf86config that comments out
the HorizSync/VertRefresh lines by default.  The library should not make
this choice, rather the config tool using the library should decide wether
or not the lines get written out.  The way it is now, is just plain broken.

Attaching patch to fix this...
Comment 1 Mike A. Harris 2004-08-28 12:09:43 UTC
Created attachment 756 [details] [review]
xorg-x11-6.7.0-libxf86config-monitor-freq-fix.patch
Comment 2 Mike A. Harris 2005-04-11 08:56:32 UTC
Comment on attachment 756 [details] [review]
xorg-x11-6.7.0-libxf86config-monitor-freq-fix.patch

This should be committed to CVS head, and also to the stable branch.
Comment 3 Mike A. Harris 2006-08-31 07:11:09 UTC
I filed this 2 years ago, dunno if the patch ever got committed to CVS or not,
but I'll assume that either it was, or that it wont ever be, so closing bug
as I'm no longer interested in tracking it.


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