drm/amd/display: Fix incorrect rounding for 10Hz refresh range

[Why]
In cases where refresh range is slightly below 10, FreeSync is not
active or supported. Need to round values before checking refresh range
in order to have FreeSync supported in these cases.

[How]
Remove redundant values and round values before checking valid refresh range.
Signed-off-by: Jaehyun Chung <jaehyun.chung@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/modules/freesync/freesync.c

@@ -32,7 +32,7 @@
 
 #define MOD_FREESYNC_MAX_CONCURRENT_STREAMS  32
 
-#define MIN_REFRESH_RANGE_IN_US 10000000
+#define MIN_REFRESH_RANGE 10
 /* Refresh rate ramp at a fixed rate of 65 Hz/second */
 #define STATIC_SCREEN_RAMP_DELTA_REFRESH_RATE_PER_FRAME ((1000 / 60) * 65)
 /* Number of elements in the render times cache array */
@@ -878,8 +878,8 @@ void mod_freesync_build_vrr_params(struct mod_freesync *mod_freesync,
 		else
 			in_out_vrr->fixed_refresh_in_uhz = 0;
 
-		refresh_range = in_out_vrr->max_refresh_in_uhz -
-				in_out_vrr->min_refresh_in_uhz;
+		refresh_range = div_u64(in_out_vrr->max_refresh_in_uhz + 500000, 1000000) -
++				div_u64(in_out_vrr->min_refresh_in_uhz + 500000, 1000000);
 
 		in_out_vrr->supported = true;
 	}
@@ -918,7 +918,7 @@ void mod_freesync_build_vrr_params(struct mod_freesync *mod_freesync,
 		in_out_vrr->adjust.v_total_min = stream->timing.v_total;
 		in_out_vrr->adjust.v_total_max = stream->timing.v_total;
 	} else if (in_out_vrr->state == VRR_STATE_ACTIVE_VARIABLE &&
-			refresh_range >= MIN_REFRESH_RANGE_IN_US) {
+			refresh_range >= MIN_REFRESH_RANGE) {
 
 		in_out_vrr->adjust.v_total_min =
 			calc_v_total_from_refresh(stream,
@@ -1105,16 +1105,10 @@ unsigned long long mod_freesync_calc_nominal_field_rate(
 	return nominal_field_rate_in_uhz;
 }
 
-bool mod_freesync_is_valid_range(struct mod_freesync *mod_freesync,
-		const struct dc_stream_state *stream,
-		uint32_t min_refresh_cap_in_uhz,
+bool mod_freesync_is_valid_range(uint32_t min_refresh_cap_in_uhz,
 		uint32_t max_refresh_cap_in_uhz,
-		uint32_t min_refresh_request_in_uhz,
-		uint32_t max_refresh_request_in_uhz)
+		uint32_t nominal_field_rate_in_uhz) 
 {
-	/* Calculate nominal field rate for stream */
-	unsigned long long nominal_field_rate_in_uhz =
-			mod_freesync_calc_nominal_field_rate(stream);
 
 	/* Typically nominal refresh calculated can have some fractional part.
 	 * Allow for some rounding error of actual video timing by taking floor
@@ -1153,8 +1147,6 @@ bool mod_freesync_is_valid_range(struct mod_freesync *mod_freesync,
 			div_u64(nominal_field_rate_in_uhz + 500000, 1000000);
 	min_refresh_cap_in_uhz /= 1000000;
 	max_refresh_cap_in_uhz /= 1000000;
-	min_refresh_request_in_uhz /= 1000000;
-	max_refresh_request_in_uhz /= 1000000;
 
 	// Check nominal is within range
 	if (nominal_field_rate_in_uhz > max_refresh_cap_in_uhz ||
@@ -1165,23 +1157,12 @@ bool mod_freesync_is_valid_range(struct mod_freesync *mod_freesync,
 	if (nominal_field_rate_in_uhz < max_refresh_cap_in_uhz)
 		max_refresh_cap_in_uhz = nominal_field_rate_in_uhz;
 
-	// Don't allow min > max
-	if (min_refresh_request_in_uhz > max_refresh_request_in_uhz)
-		return false;
-
 	// Check min is within range
-	if (min_refresh_request_in_uhz > max_refresh_cap_in_uhz ||
-		min_refresh_request_in_uhz < min_refresh_cap_in_uhz)
-		return false;
-
-	// Check max is within range
-	if (max_refresh_request_in_uhz > max_refresh_cap_in_uhz ||
-		max_refresh_request_in_uhz < min_refresh_cap_in_uhz)
+	if (min_refresh_cap_in_uhz > max_refresh_cap_in_uhz)
 		return false;
 
 	// For variable range, check for at least 10 Hz range
-	if ((max_refresh_request_in_uhz != min_refresh_request_in_uhz) &&
-		(max_refresh_request_in_uhz - min_refresh_request_in_uhz < 10))
+	if (nominal_field_rate_in_uhz - min_refresh_cap_in_uhz < 10)
 		return false;
 
 	return true;

drivers/gpu/drm/amd/display/modules/inc/mod_freesync.h

@@ -170,12 +170,9 @@ void mod_freesync_handle_v_update(struct mod_freesync *mod_freesync,
 unsigned long long mod_freesync_calc_nominal_field_rate(
 			const struct dc_stream_state *stream);
 
-bool mod_freesync_is_valid_range(struct mod_freesync *mod_freesync,
-		const struct dc_stream_state *stream,
-		uint32_t min_refresh_cap_in_uhz,
+bool mod_freesync_is_valid_range(uint32_t min_refresh_cap_in_uhz,
 		uint32_t max_refresh_cap_in_uhz,
-		uint32_t min_refresh_request_in_uhz,
-		uint32_t max_refresh_request_in_uhz);
+		uint32_t nominal_field_rate_in_uhz);