<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#c26">Comment # 26</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=90101" name="attach_90101" title="dmesg 3.13.0-rc1 with hack from comment #24">attachment 90101</a> <a href="attachment.cgi?id=90101&action=edit" title="dmesg 3.13.0-rc1 with hack from comment #24">[details]</a> dmesg 3.13.0-rc1 with hack from <a href="show_bug.cgi?id=71267#c24">comment #24</a> dmesg 3.13.0-rc1 with: - hack from <a href="show_bug.cgi?id=71267#c24">comment #24</a> - DRM_DEBUG_KMS messages before, inside and when leaving a lock on mode_config.mutex - DRM_DEBUG_KMS messages before schedule/cancel_delayed_work(_sync) on panel_vdd_work (That's why "XXX: schedule work (msecs_to_jiffies)..." shows up.) I've to recall my statement in <a href="show_bug.cgi?id=71267#c24">comment #24</a>: > I know that's not atomic. But, in case of the bug it runs into the if-clause (so, the mutex is locked) and gives a warning about an unbalanced unlock. Then it moves on and ironlake_panel_vdd_work() gets stuck when trying to lock mode_config.mutex. With the hack applied it doesn't deadlock in ironlake_panel_vdd_work() when aquiring the lock on mode_config.mutex. Comparing the dmesg output with the preemption workaround, see <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>, I miss intel_dp_set_signal_levels() and friends between haswell_write_eld() and ironlake_panel_vdd_work(). Notes on dmesg: @57.286024 I've plugged in the monitor and wait. @263.064377 More than 120s are gone and no "task kworker/xyz blocked for more than 120 seconds" message showed up. Try to start Xorg and wait. @480.271406 "INFO: task Xorg:152 blocked for more than 120 seconds." Yep, last message in Xorg.0.log is "xfree86: Adding drm device (/dev/dri/card0)". The nice retro pattern never showed up. ;) @480.307359 "INFO: lockdep is turned off." Heee? I've definitly enabled lockdep, made a `make clean && make` in the kernel tree and in /proc/config.gz I can find CONFIG_LOCKDEP=y.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>