drm/amd/display: Move the memory allocation out of dcn21_validate_bandwidth_fp().

dcn21_validate_bandwidth_fp() is invoked while FPU access has been
enabled. FPU access requires disabling preemption even on PREEMPT_RT.
It is not possible to allocate memory with disabled preemption even with
GFP_ATOMIC on PREEMPT_RT.

Move the memory allocation before FPU access is enabled.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=217928Acked-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn21/dcn21_resource.c

@@ -953,9 +953,17 @@ static bool dcn21_validate_bandwidth(struct dc *dc, struct dc_state *context,
 		bool fast_validate)
 {
 	bool voltage_supported;
+	display_e2e_pipe_params_st *pipes;
+
+	pipes = kcalloc(dc->res_pool->pipe_count, sizeof(display_e2e_pipe_params_st), GFP_KERNEL);
+	if (!pipes)
+		return false;
+
 	DC_FP_START();
-	voltage_supported = dcn21_validate_bandwidth_fp(dc, context, fast_validate);
+	voltage_supported = dcn21_validate_bandwidth_fp(dc, context, fast_validate, pipes);
 	DC_FP_END();
+
+	kfree(pipes);
 	return voltage_supported;
 }
 

drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.c

@@ -2218,9 +2218,8 @@ static void dcn21_calculate_wm(struct dc *dc, struct dc_state *context,
 						&context->bw_ctx.dml, pipes, pipe_cnt);
 }
 
-bool dcn21_validate_bandwidth_fp(struct dc *dc,
-				 struct dc_state *context,
-				 bool fast_validate)
+bool dcn21_validate_bandwidth_fp(struct dc *dc, struct dc_state *context,
+				 bool fast_validate, display_e2e_pipe_params_st *pipes)
 {
 	bool out = false;
 
@@ -2229,7 +2228,6 @@ bool dcn21_validate_bandwidth_fp(struct dc *dc,
 	int vlevel = 0;
 	int pipe_split_from[MAX_PIPES];
 	int pipe_cnt = 0;
-	display_e2e_pipe_params_st *pipes = kzalloc(dc->res_pool->pipe_count * sizeof(display_e2e_pipe_params_st), GFP_ATOMIC);
 	DC_LOGGER_INIT(dc->ctx->logger);
 
 	BW_VAL_TRACE_COUNT();
@@ -2269,7 +2267,6 @@ bool dcn21_validate_bandwidth_fp(struct dc *dc,
 	out = false;
 
 validate_out:
-	kfree(pipes);
 
 	BW_VAL_TRACE_FINISH();
 

drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.h

@@ -77,9 +77,8 @@ int dcn21_populate_dml_pipes_from_context(struct dc *dc,
 					  struct dc_state *context,
 					  display_e2e_pipe_params_st *pipes,
 					  bool fast_validate);
-bool dcn21_validate_bandwidth_fp(struct dc *dc,
-				 struct dc_state *context,
-				 bool fast_validate);
+bool dcn21_validate_bandwidth_fp(struct dc *dc, struct dc_state *context, bool
+				 fast_validate, display_e2e_pipe_params_st *pipes);
 void dcn21_update_bw_bounding_box(struct dc *dc, struct clk_bw_params *bw_params);
 
 void dcn21_clk_mgr_set_bw_params_wm_table(struct clk_bw_params *bw_params);