[bug report] drm/amd/display: Remove plane and stream pointers from dc scratch

[Dan Carpenter]

Hello Alvin Lee,

Commit 285a7054bf81 ("drm/amd/display: Remove plane and stream
pointers from dc scratch") from Mar 15, 2024 (linux-next), leads to
the following Smatch static checker warning:

drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn20/dcn20_hwseq.c:1112 dcn20_set_input_transfer_func() warn: address of 'plane_state->in_transfer_func' is non-NULL
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn10/dcn10_hwseq.c:1839 dcn10_set_input_transfer_func() warn: address of 'plane_state->in_transfer_func' is non-NULL
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dce110/dce110_hwseq.c:301 dce110_set_input_transfer_func() warn: address of 'plane_state->in_transfer_func' is non-NULL

drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn20/dcn20_hwseq.c
    1094 bool dcn20_set_input_transfer_func(struct dc *dc,
    1095                                 struct pipe_ctx *pipe_ctx,
    1096                                 const struct dc_plane_state *plane_state)
    1097 {
    1098         struct dce_hwseq *hws = dc->hwseq;
    1099         struct dpp *dpp_base = pipe_ctx->plane_res.dpp;
    1100         const struct dc_transfer_func *tf = NULL;
                                                ^^^^^^^^^
This assignment is not necessary now.

    1101         bool result = true;
    1102         bool use_degamma_ram = false;
    1103 
    1104         if (dpp_base == NULL || plane_state == NULL)
    1105                 return false;
    1106 
    1107         hws->funcs.set_shaper_3dlut(pipe_ctx, plane_state);
    1108         hws->funcs.set_blend_lut(pipe_ctx, plane_state);
    1109 
    1110         tf = &plane_state->in_transfer_func;
                 ^^^^^
Before there was an if statement but now tf is assigned unconditionally

    1111 
--> 1112         if (tf == NULL) {
                 ^^^^^^^^^^^^^^^^^
so these conditions are impossible.

    1113                 dpp_base->funcs->dpp_set_degamma(dpp_base,
    1114                                 IPP_DEGAMMA_MODE_BYPASS);
    1115                 return true;
    1116         }
    1117 
    1118         if (tf->type == TF_TYPE_HWPWL || tf->type == TF_TYPE_DISTRIBUTED_POINTS)
    1119                 use_degamma_ram = true;
    1120 
    1121         if (use_degamma_ram == true) {
    1122                 if (tf->type == TF_TYPE_HWPWL)
    1123                         dpp_base->funcs->dpp_program_degamma_pwl(dpp_base,

regards,
dan carpenter