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<body><span class="vcard"><a class="email" href="mailto:oyvinds@everdot.org" title="Öyvind Saether <oyvinds@everdot.org>"> <span class="fn">Öyvind Saether</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED NOTOURBUG - Laptop with i915 GPU hangs changing screen brightness with kernel 4.16.x, 4.15 fine."
href="https://bugs.freedesktop.org/show_bug.cgi?id=106181">bug 106181</a>
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<th>What</th>
<th>Removed</th>
<th>Added</th>
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<td style="text-align:right;">Status</td>
<td>NEW
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<td>RESOLVED
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<td style="text-align:right;">Resolution</td>
<td>---
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<td>NOTOURBUG
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED NOTOURBUG - Laptop with i915 GPU hangs changing screen brightness with kernel 4.16.x, 4.15 fine."
href="https://bugs.freedesktop.org/show_bug.cgi?id=106181#c1">Comment # 1</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED NOTOURBUG - Laptop with i915 GPU hangs changing screen brightness with kernel 4.16.x, 4.15 fine."
href="https://bugs.freedesktop.org/show_bug.cgi?id=106181">bug 106181</a>
from <span class="vcard"><a class="email" href="mailto:oyvinds@everdot.org" title="Öyvind Saether <oyvinds@everdot.org>"> <span class="fn">Öyvind Saether</span></a>
</span></b>
<pre>Further investigation and testing on this laptop with Fedora 4.16.2 and 4.16.4
and comparing configurations with 4.15.17 reveals that this Fedora
configuration change is the cause:
< CONFIG_SATA_MOBILE_LPM_POLICY=0
<span class="quote">> CONFIG_SATA_MOBILE_LPM_POLICY=3</span >
which can be fixed by adding this kernel boot parameter:
ahci.mobile_lpm_policy=1
(I guess 0 would work to, but
/sys/class/scsi_host/host*/link_power_management_policy was set to
max_performance with 0 on 4.15.17)
One Obvious Question: Why would having this set to 3 (med_power_with_dipm) make
the laptop hang immediately when changing the Screen Brightness manually (or
when redshift is running)? This seems counterintuitive and very very strange.
I can reproduce this 100%. I can even do this on 4.15.17,
for powercontrol in /sys/class/scsi_host/host*/link_power_management_policy ;
do
echo 'min_powermin_power' > $powercontrol
done
and make that one hang by changing the screen brightness. I do not understand.</pre>
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