<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - LCD flickering on Thinkpad T440p (Haswell) with kernel 4.6-rc4 (PSR enabled)" href="https://bugs.freedesktop.org/show_bug.cgi?id=95176#c36">Comment # 36</a> on <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - LCD flickering on Thinkpad T440p (Haswell) with kernel 4.6-rc4 (PSR enabled)" href="https://bugs.freedesktop.org/show_bug.cgi?id=95176">bug 95176</a> from <a class="email" href="mailto:dion@dion.org.ua" title="Dmitry Nezhevenko <dion@dion.org.ua>"> Dmitry Nezhevenko</a> <pre>It looks like something very strange happens. I'm not sure whether it's caused by patches or it's just mainline 4.6.2 behavior. I've docked my t440p laptop to dock with external monitor connected and configured internal eDP as secondary. And got followed: <a href="https://youtu.be/kfiqEOpQ1do">https://youtu.be/kfiqEOpQ1do</a> So I'm getting flickering on external monitor. But when I'm displaying watch -n 0.1 cat /sys/kernel/debug/dri/0/i915_edp_psr_status everything seems to be ok. Also when I'm typing something flickering stops for a while. dmesg contains followed: [23279.278108] [drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR* uncleared fifo underrun on pipe B [23279.278119] [drm:ironlake_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun [23393.451412] [drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR* uncleared fifo underrun on pipe B [23393.451422] [drm:ironlake_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are on the CC list for the bug.</li> </ul> </body> </html>