drm/amd/display: Toggle for Disable Force Pstate Allow on Disable

[Why & How]
In theory, driver should be able to support disabling force pstate allow
after hardware release however this behavior is not tested yet.
Introducing a new toggle to disable the force on the fly.

Reviewed-by: Dillon Varone <[email protected]>
Signed-off-by: Ryan Seto <[email protected]>
Signed-off-by: Roman Li <[email protected]>
Tested-by: Daniel Wheeler <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

Author: Ryan Seto

drivers/gpu/drm/amd/display/dc/dc.h

@@ -1073,6 +1073,7 @@ struct dc_debug_options {
 	unsigned int force_mall_ss_num_ways;
 	bool alloc_extra_way_for_cursor;
 	uint32_t subvp_extra_lines;
+	bool disable_force_pstate_allow_on_hw_release;
 	bool force_usr_allow;
 	/* uses value at boot and disables switch */
 	bool disable_dtb_ref_clk_switch;

drivers/gpu/drm/amd/display/dc/hwss/dcn401/dcn401_hwseq.c

@@ -1621,20 +1621,28 @@ void dcn401_unblank_stream(struct pipe_ctx *pipe_ctx,
 
 void dcn401_hardware_release(struct dc *dc)
 {
-	dc_dmub_srv_fams2_update_config(dc, dc->current_state, false);
-
-	/* If pstate unsupported, or still supported
-	 * by firmware, force it supported by dcn
-	 */
-	if (dc->current_state) {
-		if ((!dc->clk_mgr->clks.p_state_change_support ||
-				dc->current_state->bw_ctx.bw.dcn.fams2_global_config.features.bits.enable) &&
-				dc->res_pool->hubbub->funcs->force_pstate_change_control)
-			dc->res_pool->hubbub->funcs->force_pstate_change_control(
-					dc->res_pool->hubbub, true, true);
-
-		dc->current_state->bw_ctx.bw.dcn.clk.p_state_change_support = true;
-		dc->clk_mgr->funcs->update_clocks(dc->clk_mgr, dc->current_state, true);
+	if (!dc->debug.disable_force_pstate_allow_on_hw_release) {
+		dc_dmub_srv_fams2_update_config(dc, dc->current_state, false);
+
+		/* If pstate unsupported, or still supported
+		* by firmware, force it supported by dcn
+		*/
+		if (dc->current_state) {
+			if ((!dc->clk_mgr->clks.p_state_change_support ||
+					dc->current_state->bw_ctx.bw.dcn.fams2_global_config.features.bits.enable) &&
+					dc->res_pool->hubbub->funcs->force_pstate_change_control)
+				dc->res_pool->hubbub->funcs->force_pstate_change_control(
+						dc->res_pool->hubbub, true, true);
+
+			dc->current_state->bw_ctx.bw.dcn.clk.p_state_change_support = true;
+			dc->clk_mgr->funcs->update_clocks(dc->clk_mgr, dc->current_state, true);
+		}
+	} else {
+		if (dc->current_state) {
+			dc->clk_mgr->clks.p_state_change_support = false;
+			dc->clk_mgr->funcs->update_clocks(dc->clk_mgr, dc->current_state, true);
+		}
+		dc_dmub_srv_fams2_update_config(dc, dc->current_state, false);
 	}
 }
 

drivers/gpu/drm/amd/display/dc/resource/dcn401/dcn401_resource.c

@@ -708,6 +708,7 @@ static const struct dc_debug_options debug_defaults_drv = {
 	},
 	.use_max_lb = true,
 	.force_disable_subvp = false,
+	.disable_force_pstate_allow_on_hw_release = false,
 	.exit_idle_opt_for_cursor_updates = true,
 	.using_dml2 = true,
 	.using_dml21 = true,