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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - DisplayPort over USB-Type C Connector Not Recognised on Intel NUC8i5BEK (Gen 9, CoffeeLake)"
href="https://bugs.freedesktop.org/show_bug.cgi?id=112072">112072</a>
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<th>Summary</th>
<td>DisplayPort over USB-Type C Connector Not Recognised on Intel NUC8i5BEK (Gen 9, CoffeeLake)
</td>
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<th>Product</th>
<td>DRI
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>x86-64 (AMD64)
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<th>OS</th>
<td>Linux (All)
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>not set
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<th>Component</th>
<td>DRM/Intel
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<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
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<th>Reporter</th>
<td>geoffrey@allott.email
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<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
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<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
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<pre>I am running linux kernel 5.3.1 on an Intel NUC8i5BEK which has CoffeeLake
graphics (Intel® Iris® Plus Graphics 655).
The device has two graphics output ports, 1 HDMI and 1 USB Type-C. The kernel
reports 3 connectors; port A appears to be for embedded DisplayPort which is
reported disconnected (there is a note "Haswell uses DDI functions to detect
digital outputs. On SKL pre-D0 the strap isn't connected, so we assume it's
there.").
I've connected an ASUS ROG PG278Q Monitor to the USB Type-C port using a Type-C
to DisplayPort cable, but no video modes are reported except for the default
VGA ones, meaning I'm stuck at a resolution of 1024x768. (The monitor supports
2560x1440@144). The video output does work, though.
I have noticed that the function `bool intel_phy_is_tc(struct drm_i915_private
*dev_priv, enum phy phy)` will always return `false` for this particular GPU
(which is GEN 9).
In `static int intel_dp_get_modes(struct drm_connector *connector)` for DP-2
(the only connected connector) there is no EDID detected, it is not eDP and
there is no fixed mode; so get_modes adds no modes.
I should note that this problem occurs both on my custom kernel and on the
latest Arch Linux ISO and the latest Ubuntu ISO. The Intel UEFI-BIOS recognises
the monitor's native resolution just fine.
Here's my kernel config:
<a href="https://pastebin.com/hStMFVfE">https://pastebin.com/hStMFVfE</a>
Here's a kernel log with drm logging enabled:
<a href="https://pastebin.com/VNhZGJPu">https://pastebin.com/VNhZGJPu</a></pre>
</div>
</p>
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