| Message ID | 20201124091230.335132-1-vicamo.yang@canonical.com |
|---|---|
| Headers | show |
| Series | Add DRM support for LTTPR non-transparent link training mode | expand |
On 24.11.2020 11.12, You-Sheng Yang wrote: > BugLink: https://bugs.launchpad.net/bugs/1903969 > > [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 included 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 > > [Regression Potential] > > 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. > > Imre Deak (6): > drm/i915: Fix DP link training pattern mask > drm/i915: Simplify the link training functions > drm/i915: Factor out a helper to disable the DPCD training pattern > drm/dp: Add LTTPR helpers > drm/i915: Switch to LTTPR transparent mode link training > drm/i915: Switch to LTTPR non-transparent mode link training > > Ville Syrjälä (9): > drm/i915: s/old_crtc_state/crtc_state/ > drm/i915: Make intel_dp_process_phy_request() static > drm/i915: Shove the PHY test into the hotplug work > drm/i915: Split ICL combo PHY buf trans per output type > drm/i915: Split ICL MG PHY buf trans per output type > drm/i915: Split EHL combo PHY buf trans per output type > drm/i915: Split TGL combo PHY buf trans per output type > drm/i915: Split TGL DKL PHY buf trans per output type > drm/i915: Plumb crtc_state to link training > > drivers/gpu/drm/drm_dp_helper.c | 232 +++++++- > drivers/gpu/drm/i915/display/intel_ddi.c | 560 ++++++++++-------- > drivers/gpu/drm/i915/display/intel_ddi.h | 6 +- > .../drm/i915/display/intel_display_types.h | 19 +- > drivers/gpu/drm/i915/display/intel_dp.c | 318 +++++++--- > drivers/gpu/drm/i915/display/intel_dp.h | 11 +- > .../drm/i915/display/intel_dp_link_training.c | 554 ++++++++++++++--- > .../drm/i915/display/intel_dp_link_training.h | 17 +- > drivers/gpu/drm/i915/display/intel_dpio_phy.c | 23 +- > drivers/gpu/drm/i915/display/intel_dpio_phy.h | 2 + > drivers/gpu/drm/i915/display/intel_hdmi.c | 7 +- > include/drm/drm_dp_helper.h | 62 ++ > 12 files changed, 1355 insertions(+), 456 deletions(-) > While it's a big pile, they are queued for 5.11 and oem-5.10 is not a stable kernel yet.. applied to oem-5.10, thanks
BugLink: https://bugs.launchpad.net/bugs/1903969 [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 included 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 [Regression Potential] 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. Imre Deak (6): drm/i915: Fix DP link training pattern mask drm/i915: Simplify the link training functions drm/i915: Factor out a helper to disable the DPCD training pattern drm/dp: Add LTTPR helpers drm/i915: Switch to LTTPR transparent mode link training drm/i915: Switch to LTTPR non-transparent mode link training Ville Syrjälä (9): drm/i915: s/old_crtc_state/crtc_state/ drm/i915: Make intel_dp_process_phy_request() static drm/i915: Shove the PHY test into the hotplug work drm/i915: Split ICL combo PHY buf trans per output type drm/i915: Split ICL MG PHY buf trans per output type drm/i915: Split EHL combo PHY buf trans per output type drm/i915: Split TGL combo PHY buf trans per output type drm/i915: Split TGL DKL PHY buf trans per output type drm/i915: Plumb crtc_state to link training drivers/gpu/drm/drm_dp_helper.c | 232 +++++++- drivers/gpu/drm/i915/display/intel_ddi.c | 560 ++++++++++-------- drivers/gpu/drm/i915/display/intel_ddi.h | 6 +- .../drm/i915/display/intel_display_types.h | 19 +- drivers/gpu/drm/i915/display/intel_dp.c | 318 +++++++--- drivers/gpu/drm/i915/display/intel_dp.h | 11 +- .../drm/i915/display/intel_dp_link_training.c | 554 ++++++++++++++--- .../drm/i915/display/intel_dp_link_training.h | 17 +- drivers/gpu/drm/i915/display/intel_dpio_phy.c | 23 +- drivers/gpu/drm/i915/display/intel_dpio_phy.h | 2 + drivers/gpu/drm/i915/display/intel_hdmi.c | 7 +- include/drm/drm_dp_helper.h | 62 ++ 12 files changed, 1355 insertions(+), 456 deletions(-)