I was not able to test it on my own, this is a call for testing for the owners of these platforms. The git version of modetest now fully supports writeback. Compile libdrm/modetest from git version, run modetest -ac to determine the writeback connector, cat /sys/kernel/debug/dri/0/state to determine spare CRTC and plane, then run something like: modetest -M msm -a -s 36@85:1024x768 -o test.d -P 79@85:1024x768 where 36 is the Writeback connector id, 85 is CRTC and 79 is the plane. Then press Enter and check the test.d file for the raw image dump. Dependencies: https://patchwork.freedesktop.org/series/124832/ Dmitry Baryshkov (4): drm/msm/dpu: enable writeback on SM8150 drm/msm/dpu: enable writeback on SC8108X drm/msm/dpu: enable writeback on SM6125 drm/msm/dpu: enable writeback on SM6350 .../drm/msm/disp/dpu1/catalog/dpu_5_0_sm8150.h | 18 ++++++++++++++++++ .../msm/disp/dpu1/catalog/dpu_5_1_sc8180x.h | 18 ++++++++++++++++++ .../drm/msm/disp/dpu1/catalog/dpu_5_4_sm6125.h | 18 ++++++++++++++++++ .../drm/msm/disp/dpu1/catalog/dpu_6_4_sm6350.h | 18 ++++++++++++++++++ 4 files changed, 72 insertions(+) -- 2.39.2
