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<base href="https://bugs.freedesktop.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - eDP -> Dual Channel LVDS bridge unable to accept any modelines: Corrupt display!"
href="https://bugs.freedesktop.org/show_bug.cgi?id=112008">112008</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>eDP -> Dual Channel LVDS bridge unable to accept any modelines: Corrupt display!
</td>
</tr>
<tr>
<th>Product</th>
<td>DRI
</td>
</tr>
<tr>
<th>Version</th>
<td>DRI git
</td>
</tr>
<tr>
<th>Hardware</th>
<td>x86-64 (AMD64)
</td>
</tr>
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<th>OS</th>
<td>Linux (All)
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>major
</td>
</tr>
<tr>
<th>Priority</th>
<td>not set
</td>
</tr>
<tr>
<th>Component</th>
<td>DRM/AMDgpu
</td>
</tr>
<tr>
<th>Assignee</th>
<td>dri-devel@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>Babblebones@gmail.com
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=145745" name="attach_145745" title="kernel5.3-drm.debug=0xe">attachment 145745</a> <a href="attachment.cgi?id=145745&action=edit" title="kernel5.3-drm.debug=0xe">[details]</a></span>
kernel5.3-drm.debug=0xe
At my wits end on this bug. My bisecting have proven useless and I wanted to
get some help from you guys. Several reverted regressions reproduce the same
behavior along the way and I have spent hours sifting and booting to see where
it's at.
The short of it is that the monitor in my HP laptop boots to a 640x480 modeline
on mainline kernels newer than 4.17-rc3.
Would not be a colossal problem, as I can just force a working modeline from
userspace, if it didn't mean without the modeset the bridge utterly scrambles
the display by lining up 640x480 as a wrapping 2D length in the very top of my
screen as a jumble of colors.
The issue is GPU independent but is AMD related. Both W7170M and WX7100
affected.
Somewhere after kernel 4.17-rc3 the the rodeo begins.
My dmesg is probably going to be much much more helpful when it comes to
debugging and I will GLADLY test any kernel patches if you need more info &
detailed kernel/ custom dmesg dumps.
Notable stuff in the dump:
[ 4.773991] [drm:amdgpu_vm_init [amdgpu]] VM update mode is SDMA
[ 4.774149] [drm:drm_client_modeset_probe]
[ 4.774156] [drm:drm_helper_probe_single_connector_modes]
[CONNECTOR:59:eDP-1]
[ 4.774159] [drm:drm_helper_probe_single_connector_modes]
[CONNECTOR:59:eDP-1] status updated from unknown to connected
[ 4.774268] [drm:update_stream_scaling_settings [amdgpu]] Destination
Rectangle x:0 y:0 width:640 height:480
[ 4.774278] [drm:drm_helper_probe_single_connector_modes]
[CONNECTOR:59:eDP-1] probed modes :
[ 4.774282] [drm:drm_mode_debug_printmodeline] Modeline "640x480": 60 25175
640 656 752 800 480 490 492 525 0x40 0xa
[ 4.774284] [drm:drm_helper_probe_single_connector_modes]
[CONNECTOR:63:DP-1]</pre>
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