<html>
<head>
<base href="https://bugs.freedesktop.org/">
</head>
<body>
<p>
<div>
<b><a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED - [CI][DRMTIP] igt@pm_backlight@* - incomplete - system hang?"
href="https://bugs.freedesktop.org/show_bug.cgi?id=107820#c7">Comment # 7</a>
on <a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED - [CI][DRMTIP] igt@pm_backlight@* - incomplete - system hang?"
href="https://bugs.freedesktop.org/show_bug.cgi?id=107820">bug 107820</a>
from <span class="vcard"><a class="email" href="mailto:harish.chegondi@intel.com" title="harish.chegondi@intel.com">harish.chegondi@intel.com</a>
</span></b>
<pre>I turned on the debug messages in DRM and i915 and ran the test with the
changes mentioned in <a href="show_bug.cgi?id=107820#c6">comment #6</a> and without those changes. I have been
comparing the debug messages during the system resume step for both the cases.
One difference I found out was if the crtc was active/inactive. When I ran the
test without any changes, the crtc state was inactive during system resume.
When I ran the test with the changes in <a href="show_bug.cgi?id=107820#c6">comment #6</a>, the crtc state was active
during system resume.
I am trying to find if turning off the DPMS is setting the crtc state to
inactive and that is causing the system resume step to not turn on the
backlight.
With the changes in <a href="show_bug.cgi?id=107820#c6">comment #6</a>:
-------------------------------
[ 4341.507980] [drm:drm_atomic_helper_check_modeset [drm_kms_helper]]
[CRTC:47:pipe A] needs all connectors, enable: y, active: y
Test without any changes:
-------------------------
[ 4341.507980] [drm:drm_atomic_helper_check_modeset [drm_kms_helper]]
[CRTC:47:pipe A] needs all connectors, enable: y, active: n</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
<li>You are the QA Contact for the bug.</li>
</ul>
</body>
</html>