<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO --- - sna: (Haswell) X-server freezes when enabling DP at docking station" href="https://bugs.freedesktop.org/show_bug.cgi?id=71267#c21">Comment # 21</a> on <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO --- - sna: (Haswell) X-server freezes when enabling DP at docking station" href="https://bugs.freedesktop.org/show_bug.cgi?id=71267">bug 71267</a> from <a class="email" href="mailto:consume.noise@gmail.com" title="Daniel Martin <consume.noise@gmail.com>"> Daniel Martin</a> <pre>Created <a href="attachment.cgi?id=89947" name="attach_89947" title="dmesg 3.11 (working! - with preemption)">attachment 89947</a> <a href="attachment.cgi?id=89947&action=edit" title="dmesg 3.11 (working! - with preemption)">[details]</a> dmesg 3.11 (working! - with preemption) I've found that the option "Preemptible Kernel (Low-Latency Desktop)" can be used as a workaround for the problem. It doesn't work always, but usually. Tested with v3.9..v3.11. In the dmesg I can see the call to intel_dp_set_signal_levels() and a few others, which I don't without preemption (<a href="attachment.cgi?id=89906" name="attach_89906" title="dmesg 3.13.0-rc1">attachment 89906</a> <a href="attachment.cgi?id=89906&action=edit" title="dmesg 3.13.0-rc1">[details]</a>). So, I guess the lack of it before a call to ironlake_panel_vdd_work() is the bug? As of v3.12 this workaround doesn't work anymore. I've started to bisect it, but stopped as it was to inaccurate (as stated above, it didn't worked always for v3.9..v3.11) and time consuming. And imo it's not that predictable/representable due to preemption anyways. But, if you think that it's worth looking at it, then I could try to completly bisect it.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>