1 files changed, 96 insertions, 99 deletions

diff --git a/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c b/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
index f5b7da0e64c0..0321b4446e05 100644
--- a/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
+++ b/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
@@ -40,8 +40,15 @@ static bool dsc_policy_enable_dsc_when_not_needed;
 
 static bool dsc_policy_disable_dsc_stream_overhead;
 
+#ifndef MAX
+#define MAX(X, Y) ((X) > (Y) ? (X) : (Y))
+#endif
+#ifndef MIN
+#define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
+#endif
+
 /* Forward Declerations */
-static void get_dsc_bandwidth_range(
+static bool decide_dsc_bandwidth_range(
 		const uint32_t min_bpp_x16,
 		const uint32_t max_bpp_x16,
 		const uint32_t num_slices_h,
@@ -76,11 +83,6 @@ static bool setup_dsc_config(
 		int max_dsc_target_bpp_limit_override_x16,
 		struct dc_dsc_config *dsc_cfg);
 
-static struct fixed31_32 compute_dsc_max_bandwidth_overhead(
-		const struct dc_crtc_timing *timing,
-		const int num_slices_h,
-		const bool is_dp);
-
 static bool dsc_buff_block_size_from_dpcd(int dpcd_buff_block_size, int *buff_block_size)
 {
 
@@ -361,7 +363,7 @@ bool dc_dsc_compute_bandwidth_range(
 				dsc_min_slice_height_override, max_bpp_x16, &config);
 
 	if (is_dsc_possible)
-		get_dsc_bandwidth_range(min_bpp_x16, max_bpp_x16,
+		is_dsc_possible = decide_dsc_bandwidth_range(min_bpp_x16, max_bpp_x16,
 				config.num_slices_h, &dsc_common_caps, timing, range);
 
 	return is_dsc_possible;
@@ -462,32 +464,6 @@ static inline uint32_t dsc_div_by_10_round_up(uint32_t value)
 	return (value + 9) / 10;
 }
 
-static struct fixed31_32 compute_dsc_max_bandwidth_overhead(
-		const struct dc_crtc_timing *timing,
-		const int num_slices_h,
-		const bool is_dp)
-{
-	struct fixed31_32 max_dsc_overhead;
-	struct fixed31_32 refresh_rate;
-
-	if (dsc_policy_disable_dsc_stream_overhead || !is_dp)
-		return dc_fixpt_from_int(0);
-
-	/* use target bpp that can take entire target bandwidth */
-	refresh_rate = dc_fixpt_from_int(timing->pix_clk_100hz);
-	refresh_rate = dc_fixpt_div_int(refresh_rate, timing->h_total);
-	refresh_rate = dc_fixpt_div_int(refresh_rate, timing->v_total);
-	refresh_rate = dc_fixpt_mul_int(refresh_rate, 100);
-
-	max_dsc_overhead = dc_fixpt_from_int(num_slices_h);
-	max_dsc_overhead = dc_fixpt_mul_int(max_dsc_overhead, timing->v_total);
-	max_dsc_overhead = dc_fixpt_mul_int(max_dsc_overhead, 256);
-	max_dsc_overhead = dc_fixpt_div_int(max_dsc_overhead, 1000);
-	max_dsc_overhead = dc_fixpt_mul(max_dsc_overhead, refresh_rate);
-
-	return max_dsc_overhead;
-}
-
 static uint32_t compute_bpp_x16_from_target_bandwidth(
 	const uint32_t bandwidth_in_kbps,
 	const struct dc_crtc_timing *timing,
@@ -495,14 +471,14 @@ static uint32_t compute_bpp_x16_from_target_bandwidth(
 	const uint32_t bpp_increment_div,
 	const bool is_dp)
 {
-	struct fixed31_32 overhead_in_kbps;
+	uint32_t overhead_in_kbps;
 	struct fixed31_32 effective_bandwidth_in_kbps;
 	struct fixed31_32 bpp_x16;
 
-	overhead_in_kbps = compute_dsc_max_bandwidth_overhead(
+	overhead_in_kbps = dc_dsc_stream_bandwidth_overhead_in_kbps(
 				timing, num_slices_h, is_dp);
 	effective_bandwidth_in_kbps = dc_fixpt_from_int(bandwidth_in_kbps);
-	effective_bandwidth_in_kbps = dc_fixpt_sub(effective_bandwidth_in_kbps,
+	effective_bandwidth_in_kbps = dc_fixpt_sub_int(effective_bandwidth_in_kbps,
 			overhead_in_kbps);
 	bpp_x16 = dc_fixpt_mul_int(effective_bandwidth_in_kbps, 10);
 	bpp_x16 = dc_fixpt_div_int(bpp_x16, timing->pix_clk_100hz);
@@ -512,10 +488,12 @@ static uint32_t compute_bpp_x16_from_target_bandwidth(
 	return dc_fixpt_floor(bpp_x16);
 }
 
-/* Get DSC bandwidth range based on [min_bpp, max_bpp] target bitrate range, and timing's pixel clock
- * and uncompressed bandwidth.
+/* Decide DSC bandwidth range based on signal, timing, specs specific and input min and max
+ * requirements.
+ * The range output includes decided min/max target bpp, the respective bandwidth requirements
+ * and native timing bandwidth requirement when DSC is not used.
  */
-static void get_dsc_bandwidth_range(
+static bool decide_dsc_bandwidth_range(
 		const uint32_t min_bpp_x16,
 		const uint32_t max_bpp_x16,
 		const uint32_t num_slices_h,
@@ -523,39 +501,45 @@ static void get_dsc_bandwidth_range(
 		const struct dc_crtc_timing *timing,
 		struct dc_dsc_bw_range *range)
 {
-	/* native stream bandwidth */
-	range->stream_kbps = dc_bandwidth_in_kbps_from_timing(timing);
-
-	/* max dsc target bpp */
-	range->max_kbps = dc_dsc_stream_bandwidth_in_kbps(timing,
-			max_bpp_x16, num_slices_h, dsc_caps->is_dp);
-	range->max_target_bpp_x16 = max_bpp_x16;
-	if (range->max_kbps > range->stream_kbps) {
-		/* max dsc target bpp is capped to native bandwidth */
-		range->max_kbps = range->stream_kbps;
-		range->max_target_bpp_x16 = compute_bpp_x16_from_target_bandwidth(
-				range->max_kbps, timing, num_slices_h,
-				dsc_caps->bpp_increment_div,
-				dsc_caps->is_dp);
+	uint32_t preferred_bpp_x16 = timing->dsc_fixed_bits_per_pixel_x16;
+
+	memset(range, 0, sizeof(*range));
+
+	/* apply signal, timing, specs and explicitly specified DSC range requirements */
+	if (preferred_bpp_x16) {
+		if (preferred_bpp_x16 <= max_bpp_x16 &&
+				preferred_bpp_x16 >= min_bpp_x16) {
+			range->max_target_bpp_x16 = preferred_bpp_x16;
+			range->min_target_bpp_x16 = preferred_bpp_x16;
+		}
 	}
+	else {
+		range->max_target_bpp_x16 = max_bpp_x16;
+		range->min_target_bpp_x16 = min_bpp_x16;
+	}
+
+	/* populate output structure */
+	if (range->max_target_bpp_x16 >= range->min_target_bpp_x16 && range->min_target_bpp_x16 > 0) {
+		/* native stream bandwidth */
+		range->stream_kbps = dc_bandwidth_in_kbps_from_timing(timing);
+
+		/* max dsc target bpp */
+		range->max_kbps = dc_dsc_stream_bandwidth_in_kbps(timing,
+				range->max_target_bpp_x16, num_slices_h, dsc_caps->is_dp);
 
-	/* min dsc target bpp */
-	range->min_kbps = dc_dsc_stream_bandwidth_in_kbps(timing,
-			min_bpp_x16, num_slices_h, dsc_caps->is_dp);
-	range->min_target_bpp_x16 = min_bpp_x16;
-	if (range->min_kbps > range->max_kbps) {
-		/* min dsc target bpp is capped to max dsc bandwidth*/
-		range->min_kbps = range->max_kbps;
-		range->min_target_bpp_x16 = range->max_target_bpp_x16;
+		/* min dsc target bpp */
+		range->min_kbps = dc_dsc_stream_bandwidth_in_kbps(timing,
+				range->min_target_bpp_x16, num_slices_h, dsc_caps->is_dp);
 	}
+
+	return range->max_kbps >= range->min_kbps && range->min_kbps > 0;
 }
 
 /* Decides if DSC should be used and calculates target bpp if it should, applying DSC policy.
  *
  * Returns:
- *     - 'true' if DSC was required by policy and was successfully applied
- *     - 'false' if DSC was not necessary (e.g. if uncompressed stream fits 'target_bandwidth_kbps'),
- *        or if it couldn't be applied based on DSC policy.
+ *     - 'true' if target bpp is decided
+ *     - 'false' if target bpp cannot be decided (e.g. cannot fit even with min DSC bpp),
  */
 static bool decide_dsc_target_bpp_x16(
 		const struct dc_dsc_policy *policy,
@@ -565,40 +549,29 @@ static bool decide_dsc_target_bpp_x16(
 		const int num_slices_h,
 		int *target_bpp_x16)
 {
-	bool should_use_dsc = false;
 	struct dc_dsc_bw_range range;
 
-	memset(&range, 0, sizeof(range));
-
-	get_dsc_bandwidth_range(policy->min_target_bpp * 16, policy->max_target_bpp * 16,
-			num_slices_h, dsc_common_caps, timing, &range);
-	if (!policy->enable_dsc_when_not_needed && target_bandwidth_kbps >= range.stream_kbps) {
-		/* enough bandwidth without dsc */
-		*target_bpp_x16 = 0;
-		should_use_dsc = false;
-	} else if (policy->preferred_bpp_x16 > 0 &&
-			policy->preferred_bpp_x16 <= range.max_target_bpp_x16 &&
-			policy->preferred_bpp_x16 >= range.min_target_bpp_x16) {
-		*target_bpp_x16 = policy->preferred_bpp_x16;
-		should_use_dsc = true;
-	} else if (target_bandwidth_kbps >= range.max_kbps) {
-		/* use max target bpp allowed */
-		*target_bpp_x16 = range.max_target_bpp_x16;
-		should_use_dsc = true;
-	} else if (target_bandwidth_kbps >= range.min_kbps) {
-		/* use target bpp that can take entire target bandwidth */
-		*target_bpp_x16 = compute_bpp_x16_from_target_bandwidth(
-				target_bandwidth_kbps, timing, num_slices_h,
-				dsc_common_caps->bpp_increment_div,
-				dsc_common_caps->is_dp);
-		should_use_dsc = true;
-	} else {
-		/* not enough bandwidth to fulfill minimum requirement */
-		*target_bpp_x16 = 0;
-		should_use_dsc = false;
+	*target_bpp_x16 = 0;
+
+	if (decide_dsc_bandwidth_range(policy->min_target_bpp * 16, policy->max_target_bpp * 16,
+			num_slices_h, dsc_common_caps, timing, &range)) {
+		if (target_bandwidth_kbps >= range.stream_kbps) {
+			if (policy->enable_dsc_when_not_needed)
+				/* enable max bpp even dsc is not needed */
+				*target_bpp_x16 = range.max_target_bpp_x16;
+		} else if (target_bandwidth_kbps >= range.max_kbps) {
+			/* use max target bpp allowed */
+			*target_bpp_x16 = range.max_target_bpp_x16;
+		} else if (target_bandwidth_kbps >= range.min_kbps) {
+			/* use target bpp that can take entire target bandwidth */
+			*target_bpp_x16 = compute_bpp_x16_from_target_bandwidth(
+					target_bandwidth_kbps, timing, num_slices_h,
+					dsc_common_caps->bpp_increment_div,
+					dsc_common_caps->is_dp);
+		}
 	}
 
-	return should_use_dsc;
+	return *target_bpp_x16 != 0;
 }
 
 #define MIN_AVAILABLE_SLICES_SIZE  4
@@ -994,19 +967,45 @@ bool dc_dsc_compute_config(
 uint32_t dc_dsc_stream_bandwidth_in_kbps(const struct dc_crtc_timing *timing,
 	uint32_t bpp_x16, uint32_t num_slices_h, bool is_dp)
 {
-	struct fixed31_32 overhead_in_kbps;
+	uint32_t overhead_in_kbps;
 	struct fixed31_32 bpp;
 	struct fixed31_32 actual_bandwidth_in_kbps;
 
-	overhead_in_kbps = compute_dsc_max_bandwidth_overhead(
+	overhead_in_kbps = dc_dsc_stream_bandwidth_overhead_in_kbps(
 		timing, num_slices_h, is_dp);
 	bpp = dc_fixpt_from_fraction(bpp_x16, 16);
 	actual_bandwidth_in_kbps = dc_fixpt_from_fraction(timing->pix_clk_100hz, 10);
 	actual_bandwidth_in_kbps = dc_fixpt_mul(actual_bandwidth_in_kbps, bpp);
-	actual_bandwidth_in_kbps = dc_fixpt_add(actual_bandwidth_in_kbps, overhead_in_kbps);
+	actual_bandwidth_in_kbps = dc_fixpt_add_int(actual_bandwidth_in_kbps, overhead_in_kbps);
 	return dc_fixpt_ceil(actual_bandwidth_in_kbps);
 }
 
+uint32_t dc_dsc_stream_bandwidth_overhead_in_kbps(
+		const struct dc_crtc_timing *timing,
+		const int num_slices_h,
+		const bool is_dp)
+{
+	struct fixed31_32 max_dsc_overhead;
+	struct fixed31_32 refresh_rate;
+
+	if (dsc_policy_disable_dsc_stream_overhead || !is_dp)
+		return 0;
+
+	/* use target bpp that can take entire target bandwidth */
+	refresh_rate = dc_fixpt_from_int(timing->pix_clk_100hz);
+	refresh_rate = dc_fixpt_div_int(refresh_rate, timing->h_total);
+	refresh_rate = dc_fixpt_div_int(refresh_rate, timing->v_total);
+	refresh_rate = dc_fixpt_mul_int(refresh_rate, 100);
+
+	max_dsc_overhead = dc_fixpt_from_int(num_slices_h);
+	max_dsc_overhead = dc_fixpt_mul_int(max_dsc_overhead, timing->v_total);
+	max_dsc_overhead = dc_fixpt_mul_int(max_dsc_overhead, 256);
+	max_dsc_overhead = dc_fixpt_div_int(max_dsc_overhead, 1000);
+	max_dsc_overhead = dc_fixpt_mul(max_dsc_overhead, refresh_rate);
+
+	return dc_fixpt_ceil(max_dsc_overhead);
+}
+
 void dc_dsc_get_policy_for_timing(const struct dc_crtc_timing *timing,
 		uint32_t max_target_bpp_limit_override_x16,
 		struct dc_dsc_policy *policy)
@@ -1064,8 +1063,6 @@ void dc_dsc_get_policy_for_timing(const struct dc_crtc_timing *timing,
 		return;
 	}
 
-	policy->preferred_bpp_x16 = timing->dsc_fixed_bits_per_pixel_x16;
-
 	/* internal upper limit, default 16 bpp */
 	if (policy->max_target_bpp > dsc_policy_max_target_bpp_limit)
 		policy->max_target_bpp = dsc_policy_max_target_bpp_limit;