On Thu, Apr 24, 2025 at 02:12:15PM -0700, Rob Clark wrote: > On Wed, Apr 16, 2025 at 7:13 PM Aleksandrs Vinarskis > <alex.vinars...@gmail.com> wrote: > > > > Recently added Initial LTTPR support in msm/dp has configured LTTPR(s) > > to non-transparent mode to enable video output on X1E-based devices > > that come with LTTPR on the motherboards. However, video would not work > > if additional LTTPR(s) are present between sink and source, which is > > the case for USB Type-C docks (eg. Dell WD19TB/WD22TB4), and at least > > some universal Thunderbolt/USB Type-C monitors (eg. Dell U2725QE). > > > > First, take into account LTTPR capabilities when computing max link > > rate, number of lanes. Take into account previous discussion on the > > lists - exit early if reading DPCD caps failed. This also fixes > > "*ERROR* panel edid read failed" on some monitors which seems to be > > caused by msm_dp_panel_read_sink_caps running before LTTPR(s) are > > initialized. > > > > Finally, implement link training per-segment. Pass lttpr_count to all > > required helpers. > > This seems to also partially improve UI (Wayland) hanging when > > changing external display's link parameters (resolution, framerate): > > * Prior to this series, via direct USB Type-C to display connection, > > attempt to change resolution or framerate hangs the UI, setting does > > not stick. Some back and forth replugging finally sets desired > > parameters. > > * With this series, via direct USB Type-C to display connection, > > changing parameters works most of the time, without UI freezing. Via > > docking station/multiple LTTPRs the setting again does not stick. > > * On Xorg changing link paramaters works in all combinations. > > > > These appear to be mainlink initialization related, as in all cases LT > > passes successfully. > > > > Test matrix: > > * Dell XPS 9345, Ubuntu 24.10, Gnome 47, Wayland (myself) > > * Left USB Type-C, Right USB Type-C > > * Direct monitor connection, Dell WD19TB, Dell WD22TB4, USB > > Type-C to HDMI dongle, USB Type-C to DP dongle > > * Dell AW3423DWF, Samsung LS24A600, dual Samsung LS24A600 (one > > monitor per USB Type-C connector) > > * Dell XPS 9345, Ubuntu 24.10, Gnome 47, Wayland (myself) > > * Left USB Type-C, Right USB Type-C > > * Direct monitor connection > > * Samsung S34BG85 (USB Type-C), Dell U2725QE (universal > > Thunderbolt/USB Type-C, probes with an LTTPR when in USB > > Type-C/DP Alt mode) > > * Dell XPS 9345, Debian trixie/sid, Gnome 48, Wayland (Stefan Schmidt) > > * Left USB Type-C, Right USB Type-C > > * Dell WD15 Dock with DisplayPort connected > > * Dell HD22Q dock with HDMI connected > > * USB Type-C to HDMI dongle > > * Dell U3417W > > For the series, > > Tested-by: Rob Clark <robdcl...@gmail.com> # yoga slim 7x
Could you please send this as a response to one of the patches, so that it's also recorded by the patchwork? > > patch 4/4 had a number of conflicting hunks, you might need to rebase > on msm-next > > BR, > -R > > > In both cases, "Thunderbot Support"/"USB4 PCIE Tunneling" was disabled > > in UEFI to force universal Thunderbolt/USB Type-C devices to work in > > DP Alt mode. > > In both cases laptops had HBR3 patches applied [1], resulting in > > maximum successful link at 3440x1440@100hz and 4k@60hz respectively. > > When using Dell WD22TB4/U2725QE, USB Type-C pin assigment D got enabled > > and USB3.0 devices were working in parallel to video ouput. > > > > Known issues: > > * As mentioned above, it appears that on Gnome+Wayland framerate and > > resolution parameter adjustment is not stable. > > > > Due to lack of access to the official DisplayPort specfication, changes > > were primarily inspired by/reverse engineered from Intel's i915 driver. > > > > [1] > > https://lore.kernel.org/all/20250226231436.16138-2-alex.vinars...@gmail.com/ > > > > Signed-off-by: Aleksandrs Vinarskis <alex.vinars...@gmail.com> > > > > --- > > > > Changes in v3: > > - Split 1st patch into 3 > > - Simplified handling of max_lttpr_lanes/max_lttpr_rate > > - Moved lttpr_common_caps to msm_dp_link (not msm_dp_panel, as LTTPRs > > are link related, not panel related) > > - Picked Stefan's T-b tag (last patch only, as 1st one is getting split) > > - Droped Abel's R-b tags from 1st patch that got split due to high diff > > - Fixed alignment issues, initialization of variables, debug prints > > - Moved lttpr_count to avoid ugly pointer > > - Link to v2: > > https://lore.kernel.org/all/20250311234109.136510-1-alex.vinars...@gmail.com/ > > > > Changes in v2: > > - Picked up Abel's R-b tags > > - Fixed typo as per Abel, fixed readability as per Johan > > - Updated cover and commit message on mailink issue which appears to be > > specific to Gnome+Wayland. No problems on Xorg. > > - Link to v1: > > https://lore.kernel.org/all/20250310211039.29843-1-alex.vinars...@gmail.com/ > > > > Aleksandrs Vinarskis (4): > > drm/msm/dp: Fix support of LTTPR initialization > > drm/msm/dp: Account for LTTPRs capabilities > > drm/msm/dp: Prepare for link training per-segment for LTTPRs > > drm/msm/dp: Introduce link training per-segment for LTTPRs > > > > drivers/gpu/drm/msm/dp/dp_ctrl.c | 126 ++++++++++++++++++++-------- > > drivers/gpu/drm/msm/dp/dp_display.c | 27 ++++-- > > drivers/gpu/drm/msm/dp/dp_link.h | 4 + > > drivers/gpu/drm/msm/dp/dp_panel.c | 12 ++- > > 4 files changed, 122 insertions(+), 47 deletions(-) > > > > -- > > 2.45.2 > > -- With best wishes Dmitry
