Commit 735688eb authored by Leo Ma's avatar Leo Ma Committed by Alex Deucher
Browse files

drm/amd/display: Fix underflow issue on 175hz timing 



[Why]
Screen underflows happen on 175hz timing for 3 plane overlay case.

[How]
Based on dst y prefetch value clamp to equ or oto for bandwidth
calculation.

Reviewed-by: default avatarDillon Varone <dillon.varone@amd.com>
Acked-by: default avatarAlex Hung <alex.hung@amd.com>
Signed-off-by: default avatarLeo Ma <hanghong.ma@amd.com>
Tested-by: default avatarDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent b9f501c5

drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c

+6 −1
Original line number Diff line number Diff line
@@ -3459,6 +3459,7 @@ bool dml32_CalculatePrefetchSchedule( 
	double TimeForFetchingMetaPTE = 0;

	double TimeForFetchingRowInVBlank = 0;

	double LinesToRequestPrefetchPixelData = 0;

	double LinesForPrefetchBandwidth = 0;

	unsigned int HostVMDynamicLevelsTrips;

	double  trip_to_mem;

	double  Tvm_trips;
@@ -3888,11 +3889,15 @@ bool dml32_CalculatePrefetchSchedule( 
			TimeForFetchingMetaPTE = Tvm_oto;

			TimeForFetchingRowInVBlank = Tr0_oto;

			*PrefetchBandwidth = prefetch_bw_oto;

			/* Clamp to oto for bandwidth calculation */

			LinesForPrefetchBandwidth = dst_y_prefetch_oto;

		} else {

			*DestinationLinesForPrefetch = dst_y_prefetch_equ;

			TimeForFetchingMetaPTE = Tvm_equ;

			TimeForFetchingRowInVBlank = Tr0_equ;

			*PrefetchBandwidth = prefetch_bw_equ;

			/* Clamp to equ for bandwidth calculation */

			LinesForPrefetchBandwidth = dst_y_prefetch_equ;

		}



		*DestinationLinesToRequestVMInVBlank = dml_ceil(4.0 * TimeForFetchingMetaPTE / LineTime, 1.0) / 4.0;
@@ -3900,7 +3905,7 @@ bool dml32_CalculatePrefetchSchedule( 
		*DestinationLinesToRequestRowInVBlank =

				dml_ceil(4.0 * TimeForFetchingRowInVBlank / LineTime, 1.0) / 4.0;



		LinesToRequestPrefetchPixelData = *DestinationLinesForPrefetch -

		LinesToRequestPrefetchPixelData = LinesForPrefetchBandwidth -

				*DestinationLinesToRequestVMInVBlank - 2 * *DestinationLinesToRequestRowInVBlank;



#ifdef __DML_VBA_DEBUG__