[PATCH 25/29] drm/amd/display: Set max for prefetch lines on dcn32

[Tom Chung]

From: Dillon Varone <dillon.var...@amd.com>

[WHY?]
Max number of lines that can be used for prefetch due to type constraints is
63.75.

[HOW?]
Enforce maximum prefetch lines as 63.75.

Reviewed-by: Jun Lei <jun....@amd.com>
Acked-by: Tom Chung <chiahsuan.ch...@amd.com>
Signed-off-by: Dillon Varone <dillon.var...@amd.com>
---
 .../gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_32.h | 2 ++
 .../amd/display/dc/dml/dcn32/display_mode_vba_util_32.c    | 7 +++----
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_32.h 
b/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_32.h
index f82e14cd9d8a..c8b28c83ddf4 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_32.h
+++ b/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_32.h
@@ -46,6 +46,8 @@
 // Prefetch schedule max vratio
 #define __DML_MAX_VRATIO_PRE__ 4.0
 
+#define __DML_VBA_MAX_DST_Y_PRE__    63.75
+
 #define BPP_INVALID 0
 #define BPP_BLENDED_PIPE 0xffffffff
 
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 635fc54338fa..debe46b24a3e 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
@@ -3475,7 +3475,6 @@ bool dml32_CalculatePrefetchSchedule(
        double  min_Lsw;
        double  Tsw_est1 = 0;
        double  Tsw_est3 = 0;
-       double  TPreMargin = 0;
 
        if (v->GPUVMEnable == true && v->HostVMEnable == true)
                HostVMDynamicLevelsTrips = v->HostVMMaxNonCachedPageTableLevels;
@@ -3669,6 +3668,7 @@ bool dml32_CalculatePrefetchSchedule(
        dst_y_prefetch_equ = VStartup - (*TSetup + dml_max(TWait + TCalc, 
*Tdmdl)) / LineTime -
                        (*DSTYAfterScaler + (double) *DSTXAfterScaler / 
(double) myPipe->HTotal);
 
+       dst_y_prefetch_equ = dml_min(dst_y_prefetch_equ, 
__DML_VBA_MAX_DST_Y_PRE__);
 #ifdef __DML_VBA_DEBUG__
        dml_print("DML::%s: HTotal = %d\n", __func__, myPipe->HTotal);
        dml_print("DML::%s: min_Lsw = %f\n", __func__, min_Lsw);
@@ -3701,8 +3701,6 @@ bool dml32_CalculatePrefetchSchedule(
 
        dst_y_prefetch_equ = dml_floor(4.0 * (dst_y_prefetch_equ + 0.125), 1) / 
4.0;
        Tpre_rounded = dst_y_prefetch_equ * LineTime;
-
-       TPreMargin = Tpre_rounded - TPreReq;
 #ifdef __DML_VBA_DEBUG__
        dml_print("DML::%s: dst_y_prefetch_equ: %f (after round)\n", __func__, 
dst_y_prefetch_equ);
        dml_print("DML::%s: LineTime: %f\n", __func__, LineTime);
@@ -3730,7 +3728,8 @@ bool dml32_CalculatePrefetchSchedule(
        *VRatioPrefetchY = 0;
        *VRatioPrefetchC = 0;
        *RequiredPrefetchPixDataBWLuma = 0;
-       if (dst_y_prefetch_equ > 1 && TPreMargin > 0.0) {
+       if (dst_y_prefetch_equ > 1 &&
+                       (Tpre_rounded >= TPreReq || dst_y_prefetch_equ == 
__DML_VBA_MAX_DST_Y_PRE__)) {
                double PrefetchBandwidth1;
                double PrefetchBandwidth2;
                double PrefetchBandwidth3;
-- 
2.25.1