<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - Kernel "NULL pointer dereference" with MST monitor on HSW" href="https://bugs.freedesktop.org/show_bug.cgi?id=97666#c7">Comment # 7</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - Kernel "NULL pointer dereference" with MST monitor on HSW" href="https://bugs.freedesktop.org/show_bug.cgi?id=97666">bug 97666</a> from <a class="email" href="mailto:jim.bride@linux.intel.com" title="Jim Bride <jim.bride@linux.intel.com>"> Jim Bride</a> <pre>From looking at the dmesg Jani posted, it seems like the NULL pointer dereference is with the topology discovery / management code in the DRM driver. It's definitely the sideband worker thread that had the crash, if the stack trace is to be trusted. In Krill's case the crash happens in the frame buffer helpers, but ultimately it's likely the same condition that caused the problem. Powering down the primary monitor likely also means powering down the primary DP MST branch device in the case of powering down the first monitor in a series of daisy-chained monitors. I wouldn't necessarily expect any of the downstream monitors to work right in that case, and honestly we probably ought to be able to catch and deal with this case like an unplug event. Our drivers should handle that case gracefully, however.</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>