Merging upstream version 6.7.7.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 27 insertions, 10 deletions

diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c b/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c
index ecea008f19..80fccd4999 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c
+++ b/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c
@@ -3423,6 +3423,7 @@ bool dml32_CalculatePrefetchSchedule(
 		unsigned int SwathHeightC,
 		double TWait,
 		double TPreReq,
+		bool ExtendPrefetchIfPossible,
 		/* Output */
 		double   *DSTXAfterScaler,
 		double   *DSTYAfterScaler,
@@ -3892,12 +3893,32 @@ bool dml32_CalculatePrefetchSchedule(
 			/* 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;
+			/* For mode programming we want to extend the prefetch as much as possible
+			 * (up to oto, or as long as we can for equ) if we're not already applying
+			 * the 60us prefetch requirement. This is to avoid intermittent underflow
+			 * issues during prefetch.
+			 *
+			 * The prefetch extension is applied under the following scenarios:
+			 * 1. We're in prefetch mode > 0 (i.e. we don't support MCLK switch in blank)
+			 * 2. We're using subvp or drr methods of p-state switch, in which case we
+			 *    we don't care if prefetch takes up more of the blanking time
+			 *
+			 * Mode programming typically chooses the smallest prefetch time possible
+			 * (i.e. highest bandwidth during prefetch) presumably to create margin between
+			 * p-states / c-states that happen in vblank and prefetch. Therefore we only
+			 * apply this prefetch extension when p-state in vblank is not required (UCLK
+			 * p-states take up the most vblank time).
+			 */
+			if (ExtendPrefetchIfPossible && TPreReq == 0 && VStartup < MaxVStartup) {
+				MyError = true;
+			} 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;
@@ -4661,10 +4682,6 @@ void dml32_CalculateMinAndMaxPrefetchMode(
 	} else if (AllowForPStateChangeOrStutterInVBlankFinal == dm_prefetch_support_uclk_fclk_and_stutter) {
 		*MinPrefetchMode = 0;
 		*MaxPrefetchMode = 0;
-	} else if (AllowForPStateChangeOrStutterInVBlankFinal ==
-			dm_prefetch_support_uclk_fclk_and_stutter_if_possible) {
-		*MinPrefetchMode = 0;
-		*MaxPrefetchMode = 3;
 	} else {
 		*MinPrefetchMode = 0;
 		*MaxPrefetchMode = 3;