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<base href="https://bugs.freedesktop.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [CNL] eDP flicker at 4k"
href="https://bugs.freedesktop.org/show_bug.cgi?id=103963">103963</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[CNL] eDP flicker at 4k
</td>
</tr>
<tr>
<th>Product</th>
<td>DRI
</td>
</tr>
<tr>
<th>Version</th>
<td>DRI git
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Other
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>medium
</td>
</tr>
<tr>
<th>Component</th>
<td>DRM/Intel
</td>
</tr>
<tr>
<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>rodrigo.vivi@gmail.com
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=135787" name="attach_135787" title="reg dump bios (before i915 gets loaded)">attachment 135787</a> <a href="attachment.cgi?id=135787&action=edit" title="reg dump bios (before i915 gets loaded)">[details]</a></span>
reg dump bios (before i915 gets loaded)
After i915 takes control and do the modeset on eDP 4k screen starts flickering
badly.
No Fifounderun detected.
Just some continuously short pulses happening.
[18272.883143] [drm:intel_get_hpd_pins [i915]] hotplug event received, stat
0x01000000, dig 0x11101010, pins 0x00000010
[18272.893693] [drm:intel_hpd_irq_handler [i915]] digital hpd port A - short
[18272.900528] [drm:intel_dp_hpd_pulse [i915]] got hpd irq on port A - short
[18272.907916] [drm:intel_dp_read_dpcd [i915]] DPCD: 12 14 84 41 00 00 01 01 02
00 00 00 00 0b 00
[18274.252425] [drm:intel_get_hpd_pins [i915]] hotplug event received, stat
0x01000000, dig 0x11101010, pins 0x00000010
[18274.262964] [drm:intel_hpd_irq_handler [i915]] digital hpd port A - short
[18274.269800] [drm:intel_dp_hpd_pulse [i915]] got hpd irq on port A - short
[18274.277217] [drm:intel_dp_read_dpcd [i915]] DPCD: 12 14 84 41 00 00 01 01 02
00 00 00 00 0b 00
[18277.343929] [drm:edp_panel_vdd_off_sync [i915]] Turning eDP port A VDD off
[18277.350973] [drm:edp_panel_vdd_off_sync [i915]] PP_STATUS: 0x80000008
PP_CONTROL: 0x00000067
[18277.359426] [drm:intel_power_well_disable [i915]] disabling DC off
[18277.365650] [drm:skl_enable_dc6 [i915]] Enabling DC6
[18277.370710] [drm:gen9_set_dc_state [i915]] Setting DC state from 00 to 02
[18277.377545] [drm:intel_power_well_disable [i915]] disabling AUX A
[18278.110030] [drm:intel_get_hpd_pins [i915]] hotplug event received, stat
0x01000000, dig 0x11101010, pins 0x00000010
[18278.120569] [drm:intel_hpd_irq_handler [i915]] digital hpd port A - short
[18278.127395] [drm:intel_dp_hpd_pulse [i915]] got hpd irq on port A - short
[18278.134240] [drm:intel_power_well_enable [i915]] enabling AUX A
[18278.140175] [drm:intel_power_well_enable [i915]] enabling DC off
[18278.146234] [drm:gen9_set_dc_state [i915]] Setting DC state from 02 to 00
[18278.153137] [drm:edp_panel_vdd_on [i915]] Turning eDP port A VDD on
[18278.159690] [drm:edp_panel_vdd_on [i915]] PP_STATUS: 0x80000008 PP_CONTROL:
0x0000006f
[18278.168120] [drm:intel_dp_read_dpcd [i915]] DPCD: 12 14 84 41 00 00 01 01 02
00 00 00 00 0b 00
[18278.795277] [drm:intel_get_hpd_pins [i915]] hotplug event received, stat
0x01000000, dig 0x11101010, pins 0x00000010
[18278.805816] [drm:intel_hpd_irq_handler [i915]] digital hpd port A - short
[18278.812664] [drm:intel_dp_hpd_pulse [i915]] got hpd irq on port A - short
[18278.820033] [drm:intel_dp_read_dpcd [i915]] DPCD: 12 14 84 41 00 00 01 01 02
00 00 00 00 0b 00
[18278.831152] [drm:intel_get_hpd_pins [i915]] hotplug event received, stat
0x01000000, dig 0x11101010, pins 0x00000010
[18278.841692] [drm:intel_hpd_irq_handler [i915]] digital hpd port A - short
[18278.848548] [drm:intel_dp_hpd_pulse [i915]] got hpd irq on port A - short
[18278.855920] [drm:intel_dp_read_dpcd [i915]] DPCD: 12 14 84 41 00 00 01 01 02
00 00 00 00 0b 00
By using fastboot=1 so reusing BIOS modeset everything just work and screen
doesn't flicker at all.
I tried to little by little not re-use what BIOS has done and we start having
flicker after we train the link ourselves.
All DBuf registers are set like the BIOS ones with same level.
Changes on the vswing tables and levels doesn't solve the issue.
Disabling watermarks doesn't help either.
Disabling all pm feature like dc states, rc6, keep power wells always on plus
leaving cdclock and voltage level at maximum values helps, but doesn't solve
the issue.</pre>
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