kernel.git/drivers/gpu/drm/msm/dp/dp_ctrl.c, branch linux-6.16.y

drm/msm/dp: Introduce link training per-segment for LTTPRs

2025-05-12T16:18:49Z

DisplayPort requires per-segment link training when LTTPR are switched to non-transparent mode, starting with LTTPR closest to the source. Only when each segment is trained individually, source can link train to sink. Implement per-segment link traning when LTTPR(s) are detected, to support external docking stations. On higher level, changes are: * Pass phy being trained down to all required helpers * Run CR, EQ link training per phy * Set voltage swing, pre-emphasis levels per phy Since at least some LTTPRs (eg. Parade PS8830) do not correctly report voltage-swing, pre-emphasis level 3 support, always assume level 3 is supported. This is permitted under DP 2.1(a) section 3.6.7.2 stating that LTTPR shall set its transmitter levels as close as possible to those requested by the DPTX, if the DPTX sets the voltage swing or pre-emphasis to a level that the LTTPR does not support. It shall be noted that LTTPR’s level choosing is implementation-specific. This ensures successful link training both when connected directly to the monitor (single LTTPR onboard most X1E laptops) and via the docking station (at least two LTTPRs). Fixes: 72d0af4accd9 ("drm/msm/dp: Add support for LTTPR handling") Tested-by: Jessica Zhang # SA8775P Tested-by: Johan Hovold Tested-by: Rob Clark Tested-by: Stefan Schmidt Signed-off-by: Aleksandrs Vinarskis Reviewed-by: Abel Vesa Reviewed-by: Abhinav Kumar Reviewed-by: Dmitry Baryshkov Patchwork: https://patchwork.freedesktop.org/patch/652305/ Link: https://lore.kernel.org/r/20250507230113.14270-5-alex.vinarskis@gmail.com Signed-off-by: Dmitry Baryshkov

Merge drm/drm-next into drm-misc-next

2025-04-07T12:35:48Z

Backmerging to get v6.15-rc1 into drm-misc-next. Also fixes a build issue when enabling CONFIG_DRM_SCHED_KUNIT_TEST. Signed-off-by: Thomas Zimmermann

drm/display: dp: change drm_dp_dpcd_read_link_status() return value

2025-03-25T14:20:38Z

drm_dp_dpcd_read_link_status() follows the "return error code or number of bytes read" protocol, with the code returning less bytes than requested in case of some errors. However most of the drivers interpreted that as "return error code in case of any error". Switch drm_dp_dpcd_read_link_status() to drm_dp_dpcd_read_data() and make it follow that protocol too. Acked-by: Jani Nikula Reviewed-by: Lyude Paul Signed-off-by: Dmitry Baryshkov Link: https://lore.kernel.org/r/20250324-drm-rework-dpcd-access-v4-2-e80ff89593df@oss.qualcomm.com Signed-off-by: Dmitry Baryshkov

drm/msm: Use str_enable_disable-like helpers

2025-02-25T18:07:44Z

Replace ternary (condition ? "enable" : "disable") syntax with helpers from string_choices.h because: 1. Simple function call with one argument is easier to read. Ternary operator has three arguments and with wrapping might lead to quite long code. 2. Is slightly shorter thus also easier to read. 3. It brings uniformity in the text - same string. 4. Allows deduping by the linker, which results in a smaller binary file. Signed-off-by: Krzysztof Kozlowski Reviewed-by: Abhinav Kumar Patchwork: https://patchwork.freedesktop.org/patch/632406/ Link: https://lore.kernel.org/r/20250114191724.861601-1-krzysztof.kozlowski@linaro.org Signed-off-by: Dmitry Baryshkov

drm/msm/dp: disable the opp table request even for dp_ctrl_off_link()

2024-12-12T19:33:28Z

dp_ctrl_off_link() was created to handle a case where we received a cable connect and then get a cable disconnect without the corresponding dp_display_enable(). For such cases the pixel clock will be off but the link clock will still be on. dp_ctrl_off_link() handles this case by turning off the link clock only. However, the vote removal to the opp table for this case was missed. Remove the opp table vote in dp_ctrl_off_link(). Fixes: 375a126090b9 ("drm/msm/dp: tear down main link at unplug handle immediately") Reviewed-by: Dmitry Baryshkov Patchwork: https://patchwork.freedesktop.org/patch/627487/ Link: https://lore.kernel.org/r/20241205-dp_mst-v1-2-f8618d42a99a@quicinc.com Signed-off-by: Abhinav Kumar

drm/msm/dp: dont call dp_catalog_ctrl_mainlink_ctrl in dp_ctrl_configure_source_params()

2024-12-12T19:33:16Z

Once the link has already been setup there is no need to call dp_catalog_ctrl_mainlink_ctrl() as this does a reset on the mainlink thereby tearing down the link briefly. Fixes: c943b4948b58 ("drm/msm/dp: add displayPort driver support") Reviewed-by: Dmitry Baryshkov Patchwork: https://patchwork.freedesktop.org/patch/627479/ Link: https://lore.kernel.org/r/20241205-dp_mst-v1-1-f8618d42a99a@quicinc.com Signed-off-by: Abhinav Kumar

drm/msm/dp: prefix all symbols with msm_dp_

2024-10-31T19:08:01Z

For historical reasons a lot of symbols in the MSM DisplayPort driver used the generic dp_ prefix. Perform a mass-rename of those symbols to use msm_dp prefix. Basically this is a result of the following script: sed drivers/gpu/drm/msm/dp/* -i -e 's/\/\1/g' Yes, this also results in renaming of several struct fields in addition to renaming the structs and functions, but I think the simple solution is better than the more complex one. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202410250305.UHKDhtxy-lkp@intel.com/ Reviewed-by: Abhinav Kumar Signed-off-by: Dmitry Baryshkov Patchwork: https://patchwork.freedesktop.org/patch/622211/ Link: https://lore.kernel.org/r/20241029-msm-dp-rename-v2-1-13c5c03fad44@linaro.org

drm/msm/dp: reset the link phy params before link training

2024-08-05T20:55:26Z

Before re-starting link training reset the link phy params namely the pre-emphasis and voltage swing levels otherwise the next link training begins at the previously cached levels which can result in link training failures. Fixes: 8ede2ecc3e5e ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets") Reviewed-by: Dmitry Baryshkov Tested-by: Dmitry Baryshkov # SM8350-HDK Reviewed-by: Stephen Boyd Patchwork: https://patchwork.freedesktop.org/patch/605946/ Link: https://lore.kernel.org/r/20240725220450.131245-1-quic_abhinavk@quicinc.com Signed-off-by: Abhinav Kumar

drm/msm/dp: Removed fixed nvid "support"

2024-04-22T13:22:49Z

The "desc" member of struct dp_panel is zero-initialized during allocation and never assigned, resulting in dp_ctrl_use_fixed_nvid() never returning true. This returned boolean value is passed around but never acted upon. Perform constant propagation and remove the traces of "fixed nvid". Reviewed-by: Dmitry Baryshkov Signed-off-by: Bjorn Andersson Patchwork: https://patchwork.freedesktop.org/patch/585344/ Link: https://lore.kernel.org/r/20240328-msm-dp-cleanup-v2-2-a5aed9798d32@quicinc.com Signed-off-by: Dmitry Baryshkov

drm/msm/dp: allow voltage swing / pre emphasis of 3

2024-04-08T15:56:35Z

Both dp_link_adjust_levels() and dp_ctrl_update_vx_px() limit swing and pre-emphasis to 2, while the real maximum value for the sum of the voltage swing and pre-emphasis is 3. Fix the DP code to remove this limitation. Fixes: c943b4948b58 ("drm/msm/dp: add displayPort driver support") Signed-off-by: Dmitry Baryshkov Reviewed-by: Kuogee Hsieh Tested-by: Kuogee Hsieh Patchwork: https://patchwork.freedesktop.org/patch/577006/ Link: https://lore.kernel.org/r/20240203-dp-swing-3-v1-1-6545e1706196@linaro.org