Various removals of complex yet unnecessary math, fixing all uses of drm_dsc_config::bits_per_pixel to deal with the fact that this field includes four fractional bits, and finally making sure that range_bpg_offset contains values 6-bits wide to prevent overflows in drm_dsc_pps_payload_pack(). Altogether this series is responsible for solving _all_ Display Stream Compression issues and artifacts on the Sony Tama (sdm845) Akatsuki smartphone (2880x1440p). Changes since v2: - Generalize mux_word_size setting depending on bits_per_component; - Migrate DSI's DSC calculations to drm_dsc_compute_rc_parameters(), implicitly addressing existing math issues; - Disallow any bits_per_component other than 8, until hardcoded values are updated and tested to support such cases. v2: https://lore.kernel.org/linux-arm-msm/20221005181657.784375-1-marijn.suijten@xxxxxxxxxxxxxx/T/#u Changes since v1: - Propagate r-b's, except (obviously) in patches that were (heavily) modified; - Remove accidental debug code in dsi_cmd_dma_add; - Move Range BPG Offset masking out of DCS PPS packing, back into the DSI driver when it is assigned to drm_dsc_config (this series is now strictly focusing on drm/msm again); - Replace modulo-check resulting in conditional increment with DIV_ROUND_UP; - Remove repeated calculation of slice_chunk_size; - Use u16 instead of int when handling bits_per_pixel; - Use DRM_DEV_ERROR instead of pr_err in DSI code; - Also remove redundant target_bpp_x16 variable. v1: https://lore.kernel.org/linux-arm-msm/20221001190807.358691-1-marijn.suijten@xxxxxxxxxxxxxx/T/#u Marijn Suijten (10): drm/msm/dsi: Remove useless math in DSC calculations drm/msm/dsi: Remove repeated calculation of slice_per_intf drm/msm/dsi: Use DIV_ROUND_UP instead of conditional increment on modulo drm/msm/dsi: Reuse earlier computed dsc->slice_chunk_size drm/msm/dsi: Appropriately set dsc->mux_word_size based on bpc drm/msm/dsi: Migrate to drm_dsc_compute_rc_parameters() drm/msm/dsi: Disallow 8 BPC DSC configuration for alternative BPC values drm/msm/dsi: Account for DSC's bits_per_pixel having 4 fractional bits drm/msm/dpu1: Account for DSC's bits_per_pixel having 4 fractional bits drm/msm/dsi: Prevent signed BPG offsets from bleeding into adjacent bits drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c | 11 +- drivers/gpu/drm/msm/dsi/dsi_host.c | 121 ++++++--------------- 2 files changed, 37 insertions(+), 95 deletions(-) -- 2.38.0
