On 26/10/2022 21:28, Marijn Suijten wrote:
As per the FIXME this code is entirely duplicate with what is already provided inside drm_dsc_compute_rc_parameters(), supposedly because that function was yielding "incorrect" results while in reality the panel driver(s?) used for testing were providing incorrect parameters. For example, this code from downstream assumed dsc->bits_per_pixel to contain an integer value, whereas the upstream drm_dsc_config struct stores it with 4 fractional bits. drm_dsc_compute_rc_parameters() already accounts for this feat while the panel driver used for testing [1] wasn't, hence making drm_dsc_compute_rc_parameters() seem like it was returning an incorrect result. Other users of dsc->bits_per_pixel inside dsi_populate_dsc_params() also treat it in the same erroneous way, and will be addressed in a separate patch. In the end, using drm_dsc_compute_rc_parameters() spares both a lot of duplicate code and erratic behaviour. [1]: https://git.linaro.org/people/vinod.koul/kernel.git/commit/?h=topic/pixel3_5.18-rc1&id=1d7d98ad564f1ec69e7525e07418918d90f247a1 Fixes: b9080324d6ca ("drm/msm/dsi: add support for dsc data") Reviewed-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> Signed-off-by: Marijn Suijten <marijn.suijten@xxxxxxxxxxxxxx> --- drivers/gpu/drm/msm/dsi/dsi_host.c | 64 +++--------------------------- 1 file changed, 6 insertions(+), 58 deletions(-)
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> Thank you for the expanded explanation. -- With best wishes Dmitry
