Contributors: 21
Author Tokens Token Proportion Commits Commit Proportion
Alvin lee 1773 65.18% 15 29.41%
Dillon Varone 175 6.43% 3 5.88%
Samson Tam 147 5.40% 3 5.88%
Anthony Koo 105 3.86% 3 5.88%
Aurabindo Pillai 104 3.82% 2 3.92%
rodrigosiqueira 93 3.42% 3 5.88%
Taimur Hassan 79 2.90% 2 3.92%
Harry Wentland 79 2.90% 4 7.84%
Martin Leung 58 2.13% 1 1.96%
Eric Yang 29 1.07% 2 3.92%
Julian Parkin 28 1.03% 1 1.96%
Andrey Grodzovsky 12 0.44% 1 1.96%
Rizvi 11 0.40% 1 1.96%
Nicholas Kazlauskas 8 0.29% 1 1.96%
Dmytro Laktyushkin 6 0.22% 3 5.88%
Josip Pavic 3 0.11% 1 1.96%
Yongqiang Sun 3 0.11% 1 1.96%
Bhawanpreet Lakha 3 0.11% 1 1.96%
Jerry (Fangzhi) Zuo 2 0.07% 1 1.96%
Chris Park 1 0.04% 1 1.96%
Ilya Bakoulin 1 0.04% 1 1.96%
Total 2720 51 


/*
 * Copyright 2022 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Authors: AMD
 *
 */

// header file of functions being implemented
#include "dcn32_resource.h"
#include "dcn20/dcn20_resource.h"
#include "dml/dcn32/display_mode_vba_util_32.h"
#include "dml/dcn32/dcn32_fpu.h"

static bool is_dual_plane(enum surface_pixel_format format)
{
	return format >= SURFACE_PIXEL_FORMAT_VIDEO_BEGIN || format == SURFACE_PIXEL_FORMAT_GRPH_RGBE_ALPHA;
}


uint32_t dcn32_helper_mall_bytes_to_ways(
		struct dc *dc,
		uint32_t total_size_in_mall_bytes)
{
	uint32_t cache_lines_used, lines_per_way, total_cache_lines, num_ways;

	/* add 2 lines for worst case alignment */
	cache_lines_used = total_size_in_mall_bytes / dc->caps.cache_line_size + 2;

	total_cache_lines = dc->caps.max_cab_allocation_bytes / dc->caps.cache_line_size;
	lines_per_way = total_cache_lines / dc->caps.cache_num_ways;
	num_ways = cache_lines_used / lines_per_way;
	if (cache_lines_used % lines_per_way > 0)
		num_ways++;

	return num_ways;
}

uint32_t dcn32_helper_calculate_mall_bytes_for_cursor(
		struct dc *dc,
		struct pipe_ctx *pipe_ctx,
		bool ignore_cursor_buf)
{
	struct hubp *hubp = pipe_ctx->plane_res.hubp;
	uint32_t cursor_size = hubp->curs_attr.pitch * hubp->curs_attr.height;
	uint32_t cursor_mall_size_bytes = 0;

	switch (pipe_ctx->stream->cursor_attributes.color_format) {
	case CURSOR_MODE_MONO:
		cursor_size /= 2;
		break;
	case CURSOR_MODE_COLOR_1BIT_AND:
	case CURSOR_MODE_COLOR_PRE_MULTIPLIED_ALPHA:
	case CURSOR_MODE_COLOR_UN_PRE_MULTIPLIED_ALPHA:
		cursor_size *= 4;
		break;

	case CURSOR_MODE_COLOR_64BIT_FP_PRE_MULTIPLIED:
	case CURSOR_MODE_COLOR_64BIT_FP_UN_PRE_MULTIPLIED:
		cursor_size *= 8;
		break;
	}

	/* only count if cursor is enabled, and if additional allocation needed outside of the
	 * DCN cursor buffer
	 */
	if (pipe_ctx->stream->cursor_position.enable && (ignore_cursor_buf ||
			cursor_size > 16384)) {
		/* cursor_num_mblk = CEILING(num_cursors*cursor_width*cursor_width*cursor_Bpe/mblk_bytes, 1)
		 * Note: add 1 mblk in case of cursor misalignment
		 */
		cursor_mall_size_bytes = ((cursor_size + DCN3_2_MALL_MBLK_SIZE_BYTES - 1) /
				DCN3_2_MALL_MBLK_SIZE_BYTES + 1) * DCN3_2_MALL_MBLK_SIZE_BYTES;
	}

	return cursor_mall_size_bytes;
}

/**
 * ********************************************************************************************
 * dcn32_helper_calculate_num_ways_for_subvp: Calculate number of ways needed for SubVP
 *
 * Gets total allocation required for the phantom viewport calculated by DML in bytes and
 * converts to number of cache ways.
 *
 * @param [in] dc: current dc state
 * @param [in] context: new dc state
 *
 * @return: number of ways required for SubVP
 *
 * ********************************************************************************************
 */
uint32_t dcn32_helper_calculate_num_ways_for_subvp(
		struct dc *dc,
		struct dc_state *context)
{
	if (context->bw_ctx.bw.dcn.mall_subvp_size_bytes > 0) {
		if (dc->debug.force_subvp_num_ways) {
			return dc->debug.force_subvp_num_ways;
		} else {
			return dcn32_helper_mall_bytes_to_ways(dc, context->bw_ctx.bw.dcn.mall_subvp_size_bytes);
		}
	} else {
		return 0;
	}
}

void dcn32_merge_pipes_for_subvp(struct dc *dc,
		struct dc_state *context)
{
	uint32_t i;

	/* merge pipes if necessary */
	for (i = 0; i < dc->res_pool->pipe_count; i++) {
		struct pipe_ctx *pipe = &context->res_ctx.pipe_ctx[i];

		// For now merge all pipes for SubVP since pipe split case isn't supported yet

		/* if ODM merge we ignore mpc tree, mpo pipes will have their own flags */
		if (pipe->prev_odm_pipe) {
			/*split off odm pipe*/
			pipe->prev_odm_pipe->next_odm_pipe = pipe->next_odm_pipe;
			if (pipe->next_odm_pipe)
				pipe->next_odm_pipe->prev_odm_pipe = pipe->prev_odm_pipe;

			pipe->bottom_pipe = NULL;
			pipe->next_odm_pipe = NULL;
			pipe->plane_state = NULL;
			pipe->stream = NULL;
			pipe->top_pipe = NULL;
			pipe->prev_odm_pipe = NULL;
			if (pipe->stream_res.dsc)
				dcn20_release_dsc(&context->res_ctx, dc->res_pool, &pipe->stream_res.dsc);
			memset(&pipe->plane_res, 0, sizeof(pipe->plane_res));
			memset(&pipe->stream_res, 0, sizeof(pipe->stream_res));
		} else if (pipe->top_pipe && pipe->top_pipe->plane_state == pipe->plane_state) {
			struct pipe_ctx *top_pipe = pipe->top_pipe;
			struct pipe_ctx *bottom_pipe = pipe->bottom_pipe;

			top_pipe->bottom_pipe = bottom_pipe;
			if (bottom_pipe)
				bottom_pipe->top_pipe = top_pipe;

			pipe->top_pipe = NULL;
			pipe->bottom_pipe = NULL;
			pipe->plane_state = NULL;
			pipe->stream = NULL;
			memset(&pipe->plane_res, 0, sizeof(pipe->plane_res));
			memset(&pipe->stream_res, 0, sizeof(pipe->stream_res));
		}
	}
}

bool dcn32_all_pipes_have_stream_and_plane(struct dc *dc,
		struct dc_state *context)
{
	uint32_t i;

	for (i = 0; i < dc->res_pool->pipe_count; i++) {
		struct pipe_ctx *pipe = &context->res_ctx.pipe_ctx[i];

		if (!pipe->stream)
			continue;

		if (!pipe->plane_state)
			return false;
	}
	return true;
}

bool dcn32_subvp_in_use(struct dc *dc,
		struct dc_state *context)
{
	uint32_t i;

	for (i = 0; i < dc->res_pool->pipe_count; i++) {
		struct pipe_ctx *pipe = &context->res_ctx.pipe_ctx[i];

		if (pipe->stream && pipe->stream->mall_stream_config.type != SUBVP_NONE)
			return true;
	}
	return false;
}

bool dcn32_mpo_in_use(struct dc_state *context)
{
	uint32_t i;

	for (i = 0; i < context->stream_count; i++) {
		if (context->stream_status[i].plane_count > 1)
			return true;
	}
	return false;
}


bool dcn32_any_surfaces_rotated(struct dc *dc, struct dc_state *context)
{
	uint32_t i;

	for (i = 0; i < dc->res_pool->pipe_count; i++) {
		struct pipe_ctx *pipe = &context->res_ctx.pipe_ctx[i];

		if (!pipe->stream)
			continue;

		if (pipe->plane_state && pipe->plane_state->rotation != ROTATION_ANGLE_0)
			return true;
	}
	return false;
}

bool dcn32_is_center_timing(struct pipe_ctx *pipe)
{
	bool is_center_timing = false;

	if (pipe->stream) {
		if (pipe->stream->timing.v_addressable != pipe->stream->dst.height ||
				pipe->stream->timing.v_addressable != pipe->stream->src.height) {
			is_center_timing = true;
		}
	}

	if (pipe->plane_state) {
		if (pipe->stream->timing.v_addressable != pipe->plane_state->dst_rect.height &&
				pipe->stream->timing.v_addressable != pipe->plane_state->src_rect.height) {
			is_center_timing = true;
		}
	}

	return is_center_timing;
}

bool dcn32_is_psr_capable(struct pipe_ctx *pipe)
{
	bool psr_capable = false;

	if (pipe->stream && pipe->stream->link->psr_settings.psr_version != DC_PSR_VERSION_UNSUPPORTED) {
		psr_capable = true;
	}
	return psr_capable;
}

#define DCN3_2_NEW_DET_OVERRIDE_MIN_MULTIPLIER 7

/**
 * *******************************************************************************************
 * dcn32_determine_det_override: Determine DET allocation for each pipe
 *
 * This function determines how much DET to allocate for each pipe. The total number of
 * DET segments will be split equally among each of the streams, and after that the DET
 * segments per stream will be split equally among the planes for the given stream.
 *
 * If there is a plane that's driven by more than 1 pipe (i.e. pipe split), then the
 * number of DET for that given plane will be split among the pipes driving that plane.
 *
 * High level algorithm:
 * 1. Split total DET among number of streams
 * 2. For each stream, split DET among the planes
 * 3. For each plane, check if there is a pipe split. If yes, split the DET allocation
 *    among those pipes.
 * 4. Assign the DET override to the DML pipes.
 *
 * Special cases:
 *
 * For two displays that have a large difference in pixel rate, we may experience
 *  underflow on the larger display when we divide the DET equally. For this, we
 *  will implement a modified algorithm to assign more DET to larger display.
 *
 * 1. Calculate difference in pixel rates ( multiplier ) between two displays
 * 2. If the multiplier exceeds DCN3_2_NEW_DET_OVERRIDE_MIN_MULTIPLIER, then
 *    implement the modified DET override algorithm.
 * 3. Assign smaller DET size for lower pixel display and higher DET size for
 *    higher pixel display
 *
 * @param [in]: dc: Current DC state
 * @param [in]: context: New DC state to be programmed
 * @param [in]: pipes: Array of DML pipes
 *
 * @return: void
 *
 * *******************************************************************************************
 */
void dcn32_determine_det_override(struct dc *dc,
		struct dc_state *context,
		display_e2e_pipe_params_st *pipes)
{
	uint32_t i, j, k;
	uint8_t pipe_plane_count, stream_segments, plane_segments, pipe_segments[MAX_PIPES] = {0};
	uint8_t pipe_counted[MAX_PIPES] = {0};
	uint8_t pipe_cnt = 0;
	struct dc_plane_state *current_plane = NULL;
	uint8_t stream_count = 0;

	int phy_pix_clk_mult, lower_mode_stream_index;
	int phy_pix_clk[MAX_PIPES] = {0};
	bool use_new_det_override_algorithm = false;

	for (i = 0; i < context->stream_count; i++) {
		/* Don't count SubVP streams for DET allocation */
		if (context->streams[i]->mall_stream_config.type != SUBVP_PHANTOM) {
			phy_pix_clk[i] = context->streams[i]->phy_pix_clk;
			stream_count++;
		}
	}

	/* Check for special case with two displays, one with much higher pixel rate */
	if (stream_count == 2) {
		ASSERT((phy_pix_clk[0] > 0) && (phy_pix_clk[1] > 0));
		if (phy_pix_clk[0] < phy_pix_clk[1]) {
			lower_mode_stream_index = 0;
			phy_pix_clk_mult = phy_pix_clk[1] / phy_pix_clk[0];
		} else {
			lower_mode_stream_index = 1;
			phy_pix_clk_mult = phy_pix_clk[0] / phy_pix_clk[1];
		}

		if (phy_pix_clk_mult >= DCN3_2_NEW_DET_OVERRIDE_MIN_MULTIPLIER)
			use_new_det_override_algorithm = true;
	}

	if (stream_count > 0) {
		stream_segments = 18 / stream_count;
		for (i = 0; i < context->stream_count; i++) {
			if (context->streams[i]->mall_stream_config.type == SUBVP_PHANTOM)
				continue;

			if (use_new_det_override_algorithm) {
				if (i == lower_mode_stream_index)
					stream_segments = 4;
				else
					stream_segments = 14;
			}

			if (context->stream_status[i].plane_count > 0)
				plane_segments = stream_segments / context->stream_status[i].plane_count;
			else
				plane_segments = stream_segments;
			for (j = 0; j < dc->res_pool->pipe_count; j++) {
				pipe_plane_count = 0;
				if (context->res_ctx.pipe_ctx[j].stream == context->streams[i] &&
						pipe_counted[j] != 1) {
					/* Note: pipe_plane_count indicates the number of pipes to be used for a
					 * given plane. e.g. pipe_plane_count = 1 means single pipe (i.e. not split),
					 * pipe_plane_count = 2 means 2:1 split, etc.
					 */
					pipe_plane_count++;
					pipe_counted[j] = 1;
					current_plane = context->res_ctx.pipe_ctx[j].plane_state;
					for (k = 0; k < dc->res_pool->pipe_count; k++) {
						if (k != j && context->res_ctx.pipe_ctx[k].stream == context->streams[i] &&
								context->res_ctx.pipe_ctx[k].plane_state == current_plane) {
							pipe_plane_count++;
							pipe_counted[k] = 1;
						}
					}

					pipe_segments[j] = plane_segments / pipe_plane_count;
					for (k = 0; k < dc->res_pool->pipe_count; k++) {
						if (k != j && context->res_ctx.pipe_ctx[k].stream == context->streams[i] &&
								context->res_ctx.pipe_ctx[k].plane_state == current_plane) {
							pipe_segments[k] = plane_segments / pipe_plane_count;
						}
					}
				}
			}
		}

		for (i = 0, pipe_cnt = 0; i < dc->res_pool->pipe_count; i++) {
			if (!context->res_ctx.pipe_ctx[i].stream)
				continue;
			pipes[pipe_cnt].pipe.src.det_size_override = pipe_segments[i] * DCN3_2_DET_SEG_SIZE;
			pipe_cnt++;
		}
	} else {
		for (i = 0; i < dc->res_pool->pipe_count; i++)
			pipes[i].pipe.src.det_size_override = 4 * DCN3_2_DET_SEG_SIZE; //DCN3_2_DEFAULT_DET_SIZE
	}
}

void dcn32_set_det_allocations(struct dc *dc, struct dc_state *context,
	display_e2e_pipe_params_st *pipes)
{
	int i, pipe_cnt;
	struct resource_context *res_ctx = &context->res_ctx;
	struct pipe_ctx *pipe;
	bool disable_unbounded_requesting = dc->debug.disable_z9_mpc || dc->debug.disable_unbounded_requesting;

	for (i = 0, pipe_cnt = 0; i < dc->res_pool->pipe_count; i++) {

		if (!res_ctx->pipe_ctx[i].stream)
			continue;

		pipe = &res_ctx->pipe_ctx[i];
		pipe_cnt++;
	}

	/* For DET allocation, we don't want to use DML policy (not optimal for utilizing all
	 * the DET available for each pipe). Use the DET override input to maintain our driver
	 * policy.
	 */
	if (pipe_cnt == 1) {
		pipes[0].pipe.src.det_size_override = DCN3_2_MAX_DET_SIZE;
		if (pipe->plane_state && !disable_unbounded_requesting && pipe->plane_state->tiling_info.gfx9.swizzle != DC_SW_LINEAR) {
			if (!is_dual_plane(pipe->plane_state->format)) {
				pipes[0].pipe.src.det_size_override = DCN3_2_DEFAULT_DET_SIZE;
				pipes[0].pipe.src.unbounded_req_mode = true;
				if (pipe->plane_state->src_rect.width >= 5120 &&
					pipe->plane_state->src_rect.height >= 2880)
					pipes[0].pipe.src.det_size_override = 320; // 5K or higher
			}
		}
	} else
		dcn32_determine_det_override(dc, context, pipes);
}

/**
 * *******************************************************************************************
 * dcn32_save_mall_state: Save MALL (SubVP) state for fast validation cases
 *
 * This function saves the MALL (SubVP) case for fast validation cases. For fast validation,
 * there are situations where a shallow copy of the dc->current_state is created for the
 * validation. In this case we want to save and restore the mall config because we always
 * teardown subvp at the beginning of validation (and don't attempt to add it back if it's
 * fast validation). If we don't restore the subvp config in cases of fast validation +
 * shallow copy of the dc->current_state, the dc->current_state will have a partially
 * removed subvp state when we did not intend to remove it.
 *
 * NOTE: This function ONLY works if the streams are not moved to a different pipe in the
 *       validation. We don't expect this to happen in fast_validation=1 cases.
 *
 * @param [in]: dc: Current DC state
 * @param [in]: context: New DC state to be programmed
 * @param [out]: temp_config: struct used to cache the existing MALL state
 *
 * @return: void
 *
 * *******************************************************************************************
 */
void dcn32_save_mall_state(struct dc *dc,
		struct dc_state *context,
		struct mall_temp_config *temp_config)
{
	uint32_t i;

	for (i = 0; i < dc->res_pool->pipe_count; i++) {
		struct pipe_ctx *pipe = &context->res_ctx.pipe_ctx[i];

		if (pipe->stream)
			temp_config->mall_stream_config[i] = pipe->stream->mall_stream_config;

		if (pipe->plane_state)
			temp_config->is_phantom_plane[i] = pipe->plane_state->is_phantom;
	}
}

/**
 * *******************************************************************************************
 * dcn32_restore_mall_state: Restore MALL (SubVP) state for fast validation cases
 *
 * Restore the MALL state based on the previously saved state from dcn32_save_mall_state
 *
 * @param [in]: dc: Current DC state
 * @param [in/out]: context: New DC state to be programmed, restore MALL state into here
 * @param [in]: temp_config: struct that has the cached MALL state
 *
 * @return: void
 *
 * *******************************************************************************************
 */
void dcn32_restore_mall_state(struct dc *dc,
		struct dc_state *context,
		struct mall_temp_config *temp_config)
{
	uint32_t i;

	for (i = 0; i < dc->res_pool->pipe_count; i++) {
		struct pipe_ctx *pipe = &context->res_ctx.pipe_ctx[i];

		if (pipe->stream)
			pipe->stream->mall_stream_config = temp_config->mall_stream_config[i];

		if (pipe->plane_state)
			pipe->plane_state->is_phantom = temp_config->is_phantom_plane[i];
	}
}

#define MAX_STRETCHED_V_BLANK 1000 // in micro-seconds (must ensure to match value in FW)
/*
 * Scaling factor for v_blank stretch calculations considering timing in
 * micro-seconds and pixel clock in 100hz.
 * Note: the parenthesis are necessary to ensure the correct order of
 * operation where V_SCALE is used.
 */
#define V_SCALE (10000 / MAX_STRETCHED_V_BLANK)

static int get_frame_rate_at_max_stretch_100hz(
		struct dc_stream_state *fpo_candidate_stream,
		uint32_t fpo_vactive_margin_us)
{
	struct dc_crtc_timing *timing = NULL;
	uint32_t sec_per_100_lines;
	uint32_t max_v_blank;
	uint32_t curr_v_blank;
	uint32_t v_stretch_max;
	uint32_t stretched_frame_pix_cnt;
	uint32_t scaled_stretched_frame_pix_cnt;
	uint32_t scaled_refresh_rate;
	uint32_t v_scale;

	if (fpo_candidate_stream == NULL)
		return 0;

	/* check if refresh rate at least 120hz */
	timing = &fpo_candidate_stream->timing;
	if (timing == NULL)
		return 0;

	v_scale = 10000 / (MAX_STRETCHED_V_BLANK + fpo_vactive_margin_us);

	sec_per_100_lines = timing->pix_clk_100hz / timing->h_total + 1;
	max_v_blank = sec_per_100_lines / v_scale + 1;
	curr_v_blank = timing->v_total - timing->v_addressable;
	v_stretch_max = (max_v_blank > curr_v_blank) ? (max_v_blank - curr_v_blank) : (0);
	stretched_frame_pix_cnt = (v_stretch_max + timing->v_total) * timing->h_total;
	scaled_stretched_frame_pix_cnt = stretched_frame_pix_cnt / 10000;
	scaled_refresh_rate = (timing->pix_clk_100hz) / scaled_stretched_frame_pix_cnt + 1;

	return scaled_refresh_rate;

}

static bool is_refresh_rate_support_mclk_switch_using_fw_based_vblank_stretch(
		struct dc_stream_state *fpo_candidate_stream, uint32_t fpo_vactive_margin_us)
{
	int refresh_rate_max_stretch_100hz;
	int min_refresh_100hz;

	if (fpo_candidate_stream == NULL)
		return false;

	refresh_rate_max_stretch_100hz = get_frame_rate_at_max_stretch_100hz(fpo_candidate_stream, fpo_vactive_margin_us);
	min_refresh_100hz = fpo_candidate_stream->timing.min_refresh_in_uhz / 10000;

	if (refresh_rate_max_stretch_100hz < min_refresh_100hz)
		return false;

	return true;
}

static int get_refresh_rate(struct dc_stream_state *fpo_candidate_stream)
{
	int refresh_rate = 0;
	int h_v_total = 0;
	struct dc_crtc_timing *timing = NULL;

	if (fpo_candidate_stream == NULL)
		return 0;

	/* check if refresh rate at least 120hz */
	timing = &fpo_candidate_stream->timing;
	if (timing == NULL)
		return 0;

	h_v_total = timing->h_total * timing->v_total;
	if (h_v_total == 0)
		return 0;

	refresh_rate = ((timing->pix_clk_100hz * 100) / (h_v_total)) + 1;
	return refresh_rate;
}

/**
 * dcn32_can_support_mclk_switch_using_fw_based_vblank_stretch - Determines if config can support FPO
 *
 * @param [in]: dc - current dc state
 * @param [in]: context - new dc state
 *
 * Return: Pointer to FPO stream candidate if config can support FPO, otherwise NULL
 */
struct dc_stream_state *dcn32_can_support_mclk_switch_using_fw_based_vblank_stretch(struct dc *dc, const struct dc_state *context)
{
	int refresh_rate = 0;
	const int minimum_refreshrate_supported = 120;
	struct dc_stream_state *fpo_candidate_stream = NULL;
	bool is_fpo_vactive = false;
	uint32_t fpo_vactive_margin_us = 0;

	if (context == NULL)
		return NULL;

	if (dc->debug.disable_fams)
		return NULL;

	if (!dc->caps.dmub_caps.mclk_sw)
		return NULL;

	if (context->bw_ctx.bw.dcn.clk.fw_based_mclk_switching_shut_down)
		return NULL;

	/* For FPO we can support up to 2 display configs if:
	 * - first display uses FPO
	 * - Second display switches in VACTIVE */
	if (context->stream_count > 2)
		return NULL;
	else if (context->stream_count == 2) {
		DC_FP_START();
		dcn32_assign_fpo_vactive_candidate(dc, context, &fpo_candidate_stream);
		DC_FP_END();

		DC_FP_START();
		is_fpo_vactive = dcn32_find_vactive_pipe(dc, context, DCN3_2_MIN_ACTIVE_SWITCH_MARGIN_FPO_US);
		DC_FP_END();
		if (!is_fpo_vactive || dc->debug.disable_fpo_vactive)
			return NULL;
	} else
		fpo_candidate_stream = context->streams[0];

	if (!fpo_candidate_stream)
		return NULL;

	if (fpo_candidate_stream->sink->edid_caps.panel_patch.disable_fams)
		return NULL;

	refresh_rate = get_refresh_rate(fpo_candidate_stream);
	if (refresh_rate < minimum_refreshrate_supported)
		return NULL;

	fpo_vactive_margin_us = is_fpo_vactive ? dc->debug.fpo_vactive_margin_us : 0; // For now hardcode the FPO + Vactive stretch margin to be 2000us
	if (!is_refresh_rate_support_mclk_switch_using_fw_based_vblank_stretch(fpo_candidate_stream, fpo_vactive_margin_us))
		return NULL;

	// check if freesync enabled
	if (!fpo_candidate_stream->allow_freesync)
		return NULL;

	if (fpo_candidate_stream->vrr_active_variable)
		return NULL;

	return fpo_candidate_stream;
}