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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<title>ddcui - Limitations</title>
</head>
<h3>Fundamental Limitations</h3>
<p>
Inadequacies in the DDC/CI design, and its marginal implementation in many monitors,
lead to some problems for which <ddcui>ddcui</ddcui> has no good workaround.
<ul>
<li>Actual monitor settings may not match those reported by <strong>ddcui</strong></li>
<ul>
<li>Some monitors will change their state (e.g. red gain) when the value in the GUI changes.
However, the value reported by the monitor is unchanged.
</li>
<li>Conversely, some monitors report a newly set value, but the observed state of the monitor
is unchanged.
</li>
<li>Monitor settings can be changed by another program, including the command like program <strong>ddcutil</strong>
</li>
<li>If feature values are changed using the monitor's On Screen Display. The DDC/CI specification includes a
mechanism for informing a program of changes made using the OSD. In practice, this facility cannot be relied on.
</li>
<li>The DDC/CI and Monitor Control Command Set specifications are old. Advanced features of recent monitors,
such as Picture-by-Picture were simply not envisioned and have no (at least documented) integration to the Virtual Control Panel.
</li>
</ul>
<li>
It is possible for feature values reported in **ddcui** to become out of sync with actual monitor
values.
<ul>
<li>If feature values are changed using the monitor's On Screen Display.
</li>
<li>If feature values are changed by another program, including the command line program **ddcutil**.
</li>
<li>Some monitors will change their state (e.g. red gain) when the value in the GUI changes.
However, the value reported by the monitor is unchanged.
</li>
<li>
Conversely, some monitors report a newly set value, but the observed state of the monitor
is unchanged.
</li>
</ul>
<h3>Implementation</h3>
<p>
<ul>
<li><strong>ddcui</strong> does not detect that a monitor has been connected or disconnected.
The program must be restarted.
</li>
<li>The value of various special feature codes is not interpreted, but instead simply reported as bytes.
Interpretations of these feature codes will be added with time.
</li>
</ul>
</body>
</html>
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