<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - [bdw edp] Screen Flickering" href="https://bugs.freedesktop.org/show_bug.cgi?id=91393#c44">Comment # 44</a> on <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - [bdw edp] Screen Flickering" href="https://bugs.freedesktop.org/show_bug.cgi?id=91393">bug 91393</a> from <a class="email" href="mailto:flux242@gmail.com" title="flux242 <flux242@gmail.com>"> flux242</a> <pre>(In reply to flux242 from <a href="show_bug.cgi?id=91393#c43">comment #43</a>) > hi, I'm also experiencing bad flickering of my laptop screen. > I have installed xubuntu 15.10 on Acer C740: > > a@chrome:~$ sudo lshw -c video > *-display > description: VGA compatible controller > product: Broadwell-U Integrated Graphics > vendor: Intel Corporation > physical id: 2 > bus info: pci@0000:00:02.0 > version: 08 > width: 64 bits > clock: 33MHz > capabilities: msi pm vga_controller bus_master cap_list rom > configuration: driver=i915 latency=0 > resources: irq:43 memory:e0000000-e0ffffff memory:d0000000-dfffffff > ioport:1800(size=64) > > a@chrome:~$ uname -a > Linux chrome 4.2.0-19-generic #23-Ubuntu SMP Wed Nov 11 11:39:30 UTC 2015 > x86_64 x86_64 x86_64 GNU/Linux > > But today display was blanked after 15 minutes of inactivity and when I > woken it up I saw no more flickering and this kernel message: > Dec 5 10:16:48 chrome kernel: [ 3708.390613] [drm:intel_dp_start_link_train > [i915]] *ERROR* failed to enable link training > > please suggest a way (usingn a kernel parameter) to disable link training > until a bugfix is backported I need to add some additional info. Ive managed to reproduce the case when after screen blanking there's no flickering anymore. I start the 'xset dpms force off' command to blank the screen and after a pause I press a button to wake it up. Below is a pastebin when flickering persist after waking up: <a href="http://pastebin.com/fuY57tMH">http://pastebin.com/fuY57tMH</a> And here is a pastebin when the flickering is gone after waking up: <a href="http://pastebin.com/4gGMTycL">http://pastebin.com/4gGMTycL</a> It was really difficult to reproduce the case when the flicker is gone</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>