https://bugzilla.kernel.org/show_bug.cgi?id=217545 Bug ID: 217545 Summary: Serious regression on amdgpu (drm_display_helper/drm_dp_atomic_find_time_slots) with two DisplayPort connected via a HP G5 docking station Product: Drivers Version: 2.5 Kernel Version: 6.1 Hardware: All OS: Linux Status: NEW Severity: normal Priority: P3 Component: Video(DRI - non Intel) Assignee: drivers_video-dri@xxxxxxxxxxxxxxxxxxxx Reporter: bugzilla.kernel.bpeb@xxxxxxxxxxxxxxxxxx Regression: Yes Created attachment 304404 --> https://bugzilla.kernel.org/attachment.cgi?id=304404&action=edit lscpi This was previously mentioned in comment 69 in https://bugzilla.kernel.org/show_bug.cgi?id=204181 but I reckon it's a different story. Hardware: * Notebook hp mt45 with 03:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Picasso/Raven 2 [Radeon Vega Series / Radeon Vega Mobile Series] [1002:15d8] (rev d3) Also briefly confirmed with a Thinkpad T495 with 06:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Picasso/Raven 2 [Radeon Vega Series / Radeon Vega Mobile Series] [1002:15d8] (rev d2) * HP G5 USB-C docking station (HSN-IX02) Problem: After upgrading from kernel 6.0 to 6.1, the host crashes once a *second* external display is connected via DisplayPort on that docking station: BUG: kernel NULL pointer dereference, address: 0000000000000008 RIP: 0010:drm_dp_atomic_find_time_slots+0x47/0x250 [drm_display_helper] (see attachment for full log) Another way to reproduce this: * Use the Ubuntu 23.04 installer/test image. * Boot with displays disconnected. * Select "Try Ubuntu". * Connect displays. * Upon connecting the second display, the system freezes. Insights found after bisecting: * This was introduced with commit commit a5c2c0d164e96d24f73faffcd3b7bbb607e701a9 Author: Lyude Paul <lyude@xxxxxxxxxx> Date: Wed Aug 17 15:38:37 2022 -0400 drm/display/dp_mst: Add nonblocking helpers for DP MST * Later this was half-fixed with commit commit efa4c4df864ecd969670093524d3e8f69188e5eb Author: Harry Wentland <harry.wentland@xxxxxxx> Date: Mon Feb 13 17:36:55 2023 -0500 drm/amd/display: call remove_stream_from_ctx from res_pool funcs Now the notebook no longer crashes, however the displays remain dark although from the operating system's point of view they are connected and should show some content. This may or may not be a userland problem. (Aside: This commit should be backported to the 6.1 stable series. It applies and likewise reduces the problem from "crash" to "dark screens" there.) This situation still exists with 6.4-rc6 (released last night) Please advise if there's anything else we can do. Find attached: * lscpi * dmesg (with drm.debug=4) * kernel.log (the actual crash) -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
