<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - Screen is frozen on second connection of DP MST dock" href="https://bugs.freedesktop.org/show_bug.cgi?id=107546#c2">Comment # 2</a> on <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - Screen is frozen on second connection of DP MST dock" href="https://bugs.freedesktop.org/show_bug.cgi?id=107546">bug 107546</a> from <a class="email" href="mailto:stanislav.lisovskiy@intel.com" title="Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>"> Stanislav Lisovskiy</a> <pre>(In reply to Sergey Menshikov from <a href="show_bug.cgi?id=107546#c0">comment #0</a>) > Kernel 4.15.0.30 Ubuntu 18.04.1 Xorg/Gnome Lenovo 4th gen X1 20FBxxx Skylake > i7 Intel built-in video, Lenovo OneLink+ DP MST dock with dual dell 24" > displays > > Error messages upon dock disconnect: > > [drm:intel_dp_start_link_train [i915]] *ERROR* failed to enable link training > [drm:intel_mst_pre_enable_dp [i915]] *ERROR* failed to allocate vcpi > > Next connection leads to frozen screen on laptop, no change on exterenal > monitors. > > [drm:intel_wait_ddi_buf_idle [i915]] *ERROR* Timeout waiting for DDI BUF C > idle bit > > Disconnecting the dock restores laptop screen functionality, but subsequent > connection of the dock has the same symptoms repeating. Reboot fixes the > issue until first dock disconnect. > Does it happen only to Laptop integrated screen? This might be a duplicate of <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED - Regression with Dell TB16 dock and Linux kernel 4.16.x" href="show_bug.cgi?id=106250">https://bugs.freedesktop.org/show_bug.cgi?id=106250</a>, which in fact consists of two different bugs: one is related to watermark calculation algorithm, basically exceeding available resources for Y Tiled framebuffer for 4K screenmodes - which manifests as black laptop integrated screen and if you enable drm.debug=0x14, you should see some complaints regarding exceeding available ddb_allocation. Another bug, which it might be related to is that sometimes we don't get RRSetCrtcConfig request from X Server client, upon receiving the hotplug event, which results in not receiving drm_mode_setcrtc call for one of the screeens. This one seems to affect external displays and happens every second time you plug/unplug external display. So please attach dmesg traces with drm.debug=0x14 enabled, so that we could differentiate if its a duplicate or something else. Also you can try to manually enable the screen by using xrandr --output (output name) --crtc (number) - try different crtc numbers here, if it helps it might also mean that we simply don't get the modesetting call.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> <li>You are on the CC list for the bug.</li> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>