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<base href="https://bugs.freedesktop.org/" />
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<th>Priority</th>
<td>medium
</td>
</tr>
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - output name duplication for providers #1 and up"
href="https://bugs.freedesktop.org/show_bug.cgi?id=79531">79531</a>
</td>
</tr>
<tr>
<th>Assignee</th>
<td>xorg-driver-ati@lists.x.org
</td>
</tr>
<tr>
<th>Summary</th>
<td>output name duplication for providers #1 and up
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>xorg-team@lists.x.org
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux (All)
</td>
</tr>
<tr>
<th>Reporter</th>
<td>gmt@be-evil.net
</td>
</tr>
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<th>Hardware</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Version</th>
<td>git
</td>
</tr>
<tr>
<th>Component</th>
<td>Driver/Radeon
</td>
</tr>
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<th>Product</th>
<td>xorg
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=100274" name="attach_100274" title="churn_output_names.patch">attachment 100274</a> <a href="attachment.cgi?id=100274&action=edit" title="churn_output_names.patch">[details]</a></span>
churn_output_names.patch
Thanks to a Dave Airlie and others in irc for helping me get to the bottom of
this.
For cards other than "#0" (I'm still quite unclear on where exactly the
numbering comes from -- I presume it's the same place as the /dev/dri/card*
specials), it is still quite possible to get duplicated output names.
This is because the code identified in the source as "for compatibility with
UMS output names" does not run; instead, for these non-#0-cards, only the
human-readable output type name (i.e.: "DVI", "HDMI", etc.) differentiates the
various outputs. Unfortunately these names are not at all unique:
const char *output_names[] = {
"None",
"VGA",
"DVI",
"DVI",
"DVI",
"Composite",
"S-video",
"LVDS",
"CTV",
"DIN",
"DisplayPort",
"HDMI",
"HDMI",
"TV",
"eDP"
};
The result, depending on your hardware: adding a second card results in
duplicate output names in the global randr namespace. Wouldn't be so terrible,
except it makes xrandr go utterly berzerk.*
Rather than pile more output numbering kludges on top of the ones already in
drmmode_output_init, folks in IRC seemed to agree that a better solution would
be to go ahead and allow the output names to churn and replace the duplicate
values in the above array with unique ones.
I posted this to the mailing list some days ago and no flame-war ensued. But,
I'm new in town; perhaps bugzilla is a better way to get my patch looked at?
* This may represent a second bug in apps/xrandr, as I noticed several
third-party consumers of libXrandr continued to work correctly in spite of the
duplicate names; however, apps/xrandr always freaked out, even if I only fed it
XID's.</pre>
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