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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - MST (multi stream) with Asus PQ321 drm_dp_calc_pbn_mode() fails"
href="https://bugs.freedesktop.org/show_bug.cgi?id=91789">91789</a>
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<th>Summary</th>
<td>MST (multi stream) with Asus PQ321 drm_dp_calc_pbn_mode() fails
</td>
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<th>Product</th>
<td>DRI
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<th>Version</th>
<td>unspecified
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<th>Hardware</th>
<td>x86 (IA32)
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<th>OS</th>
<td>Linux (All)
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>normal
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<th>Priority</th>
<td>medium
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<th>Component</th>
<td>General
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<th>Assignee</th>
<td>dri-devel@lists.freedesktop.org
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<th>Reporter</th>
<td>Peter.Blum@lxco.com
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<p>
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<pre>If a Asus monitor PQ321 is used in MST mode it gets no signal.
This is because the function drm_dp_calc_pbn_mode() in drm_dp_mst_topology.c
returns a bad pixel bandwith number for the mode
Modeline 131:"1920x2160" 60 297000 1920 2008 2052 2200 2160 2168 2178 2250 0x48
0x5
The function return 8 and not the correct value of 1063.
Using simple u32 arithmetic in drm_dp_calc_pbn_mode() the monitor works fine.
I'm not sure if unsigned 32 bit would overflow in some cases.</pre>
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