https://bugs.freedesktop.org/show_bug.cgi?id=91481
--- Comment #1 from Adam J. Richter adam_richter2004@yahoo.com --- Thank you, Dave Arlie, and anyone else involved, for the DisplayPort MultiStream Transport fixes in Linux 4.1.6 and 4.2 (and a few of the subreleases and release candidates leading up to these versions).
However, I think that some change along the lines of the patch that I mentioned may still be necessary. I cannot be sure, because when I try to boot linux-4.1.6, I get a other kernels bugs either before I get a chance to test this or while I am testing it. I am pretty sure I tried Linux-4.2 and observed the kernel getting fault that would go away when I would apply the attached patch.
It looks to me like, toward the end of drm_dp_add_port in Linux-4.2, I still see the following code:
drm_dp_send_link_address(mstb->mgr, port->mstb); port->mstb->link_address_sent = true;
...and drm_dp_send_link_address has this line, which I think can call a function that can change port->mstb:
(*mgr->cbs->hotplug)(mgr);