[PATCH] drm/amdgpu/display: fix FP handling in DCN30

[Alex Deucher]

On Thu, Nov 12, 2020 at 5:06 PM Bhawanpreet Lakha
<Bhawanpreet.Lakha at amd.com> wrote:
>
> From: Alex Deucher <alexander.deucher at amd.com>
>
> Adjust the FP handling to avoid nested calls.
>
> The nested calls cause the warning below
> WARNING: CPU: 3 PID: 384 at arch/x86/kernel/fpu/core.c:129 kernel_fpu_begin
>
> Fixes: 26803606c5d6 ("drm/amdgpu/display: FP fixes for DCN3.x (v4)")
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha at amd.com>

Looks good to me.  Thanks!

Alex

> ---
>  .../drm/amd/display/dc/dcn30/dcn30_resource.c | 43 +++----------------
>  1 file changed, 6 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_resource.c b/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_resource.c
> index b379057e669c..d5c81ad55045 100644
> --- a/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_resource.c
> +++ b/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_resource.c
> @@ -1470,20 +1470,8 @@ int dcn30_populate_dml_pipes_from_context(
>         return pipe_cnt;
>  }
>
> -/*
> - * This must be noinline to ensure anything that deals with FP registers
> - * is contained within this call; previously our compiling with hard-float
> - * would result in fp instructions being emitted outside of the boundaries
> - * of the DC_FP_START/END macros, which makes sense as the compiler has no
> - * idea about what is wrapped and what is not
> - *
> - * This is largely just a workaround to avoid breakage introduced with 5.6,
> - * ideally all fp-using code should be moved into its own file, only that
> - * should be compiled with hard-float, and all code exported from there
> - * should be strictly wrapped with DC_FP_START/END
> - */
> -static noinline void dcn30_populate_dml_writeback_from_context_fp(
> -               struct dc *dc, struct resource_context *res_ctx, display_e2e_pipe_params_st *pipes)
> +void dcn30_populate_dml_writeback_from_context(
> +       struct dc *dc, struct resource_context *res_ctx, display_e2e_pipe_params_st *pipes)
>  {
>         int pipe_cnt, i, j;
>         double max_calc_writeback_dispclk;
> @@ -1571,14 +1559,6 @@ static noinline void dcn30_populate_dml_writeback_from_context_fp(
>
>  }
>
> -void dcn30_populate_dml_writeback_from_context(
> -               struct dc *dc, struct resource_context *res_ctx, display_e2e_pipe_params_st *pipes)
> -{
> -       DC_FP_START();
> -       dcn30_populate_dml_writeback_from_context_fp(dc, res_ctx, pipes);
> -       DC_FP_END();
> -}
> -
>  unsigned int dcn30_calc_max_scaled_time(
>                 unsigned int time_per_pixel,
>                 enum mmhubbub_wbif_mode mode,
> @@ -1977,7 +1957,7 @@ static struct pipe_ctx *dcn30_find_split_pipe(
>         return pipe;
>  }
>
> -static bool dcn30_internal_validate_bw(
> +static noinline bool dcn30_internal_validate_bw(
>                 struct dc *dc,
>                 struct dc_state *context,
>                 display_e2e_pipe_params_st *pipes,
> @@ -1999,6 +1979,7 @@ static bool dcn30_internal_validate_bw(
>
>         pipe_cnt = dc->res_pool->funcs->populate_dml_pipes(dc, context, pipes, fast_validate);
>
> +       DC_FP_START();
>         if (!pipe_cnt) {
>                 out = true;
>                 goto validate_out;
> @@ -2222,6 +2203,7 @@ static bool dcn30_internal_validate_bw(
>         out = false;
>
>  validate_out:
> +       DC_FP_END();
>         return out;
>  }
>
> @@ -2404,7 +2386,7 @@ void dcn30_calculate_wm_and_dlg(
>         DC_FP_END();
>  }
>
> -static noinline bool dcn30_validate_bandwidth_fp(struct dc *dc,
> +bool dcn30_validate_bandwidth(struct dc *dc,
>                 struct dc_state *context,
>                 bool fast_validate)
>  {
> @@ -2455,19 +2437,6 @@ static noinline bool dcn30_validate_bandwidth_fp(struct dc *dc,
>         return out;
>  }
>
> -bool dcn30_validate_bandwidth(struct dc *dc,
> -               struct dc_state *context,
> -               bool fast_validate)
> -{
> -       bool out;
> -
> -       DC_FP_START();
> -       out = dcn30_validate_bandwidth_fp(dc, context, fast_validate);
> -       DC_FP_END();
> -
> -       return out;
> -}
> -
>  static noinline void get_optimal_dcfclk_fclk_for_uclk(unsigned int uclk_mts,
>                                                         unsigned int *optimal_dcfclk,
>                                                         unsigned int *optimal_fclk)
> --
> 2.25.1
>
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