** Tags added: originate-from-1907526 -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-oem-5.6 in Ubuntu. https://bugs.launchpad.net/bugs/1903969
Title: failed to boot to GUI: i915 0000:00:02.0: [drm] *ERROR* Link Training Unsuccessful Status in HWE Next: New Status in linux package in Ubuntu: In Progress Status in linux-oem-5.10 package in Ubuntu: Invalid Status in linux-oem-5.6 package in Ubuntu: Invalid Status in linux source package in Focal: Invalid Status in linux-oem-5.10 source package in Focal: Fix Committed Status in linux-oem-5.6 source package in Focal: Won't Fix Status in linux source package in Groovy: Won't Fix Status in linux-oem-5.10 source package in Groovy: Invalid Status in linux-oem-5.6 source package in Groovy: Invalid Status in linux source package in Hirsute: In Progress Status in linux-oem-5.10 source package in Hirsute: Invalid Status in linux-oem-5.6 source package in Hirsute: Invalid Bug description: [SRU Justification] [Impact] On platforms supported DP tunneling over USB 3.2 or so, a Retimer is required on the host side to cover insertion loss. On such platforms the rtimer firmware maybe configured to use LTTPR (Link Training Tunable PHY Repeater) non-transparent mode only, which is only supported in drm-tip currently. Without LTTPR support, link training may fail with following error messages depending on the data path configuration: i915 0000:00:02.0: [drm] *ERROR* Link Training Unsuccessful i915 0000:00:02.0: [drm] *ERROR* CPU pipe A FIFO underrun [Fix] Patchset https://www.spinics.net/lists/intel-gfx/msg248700.html ("drm/i915: Add support for LTTPR non-transparent link training mode") is required to fix this issue. It has been landed to drm-tip and will only be merged to mainline in v5.11. Patchset https://patchwork.freedesktop.org/series/76993/ ("Plumb crtc state to link training code") is included for link training functions prototype changes. [Test Case] On Dell OptiPlex and WD19 docking station, use following steps to verify: 1. disconnect WD19 from OptiPlex, disconnect OptiPlex's power 2. attach OptiPlex's power cord 3. attach WD19's power cord 4. attach DP to WD19 5. attach WD19 to OptiPlex 6. boot up and check if boot to GUI directly 7. `dmesg` and check if aforementioned DRM link training error appears [Where problems could occur] The second patchset pulled for dependency doesn't have too much effective changes but refactoring some translation functions, so very unlikely to have regressions. For the major part, LTTPR support, when LTTPR is either not detected or not supported, it will fall back to use transparent mode as it was. Otherwise, DP Standard recommends to use LTTPR non-transparent mode for link training, so this should be the right way to have best hardware support. ========== original bug description ========== [Summary] When the monitor ONLY is connected to the WD19 (DP port) and WD19 is connected to the type c port than boot the machine, the monitor shows no video output after loaded i915. [Reproduce Steps] 1. connect power cable of WD19 2. connect DP cable from monitor to WD19 3. connect power cable to target system. 4. connect type c cable from WD19 to target system 5. boot up [Results] Expected: video output as there is only one monitor connected. Actual: No video output. ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: linux-image-5.6.0-1033-oem 5.6.0-1033.35 ProcVersionSignature: Ubuntu 5.6.0-1033.35-oem 5.6.19 Uname: Linux 5.6.0-1033-oem x86_64 ApportVersion: 2.20.11-0ubuntu27.11 Architecture: amd64 CasperMD5CheckResult: skip Date: Thu Nov 12 05:11:11 2020 DistributionChannelDescriptor: # This is the distribution channel descriptor for the OEM CDs # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor canonical-oem-somerville-focal-amd64-20200502-85+fossa-metapod+X40 InstallationDate: Installed on 2020-11-03 (9 days ago) InstallationMedia: Ubuntu 20.04 "Focal" - Build amd64 LIVE Binary 20200502-05:58 SourcePackage: linux-signed-oem-5.6 UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/hwe-next/+bug/1903969/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
