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authorVictor Lu <victorchengchi.lu@amd.com>2021-07-08 14:50:48 -0400
committerAlex Deucher <alexander.deucher@amd.com>2021-07-27 12:43:09 -0400
commitc8f8e96805b54968b4d1d54850f87fc39128a532 (patch)
treeabffd449db79405d305286ff3c1e64c8f6dbfeb7
parent91e273712ab8dd8c31924ac7714b21e011137e98 (diff)
drm/amd/display: Guard DST_Y_PREFETCH register overflow in DCN21
[why] DST_Y_PREFETCH can overflow when DestinationLinesForPrefetch values are too large due to the former being limited to 8 bits. [how] Set the maximum value of DestinationLinesForPrefetch to be 255 * refclk period. Reviewed-by: Laktyushkin Dmytro <dmytro.laktyushkin@amd.com> Acked-by: Solomon Chiu <solomon.chiu@amd.com> Signed-off-by: Victor Lu <victorchengchi.lu@amd.com> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
-rw-r--r--drivers/gpu/drm/amd/display/dc/dml/dcn21/display_mode_vba_21.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn21/display_mode_vba_21.c b/drivers/gpu/drm/amd/display/dc/dml/dcn21/display_mode_vba_21.c
index d25a7d38d21f..6655bb99fdfd 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/dcn21/display_mode_vba_21.c
+++ b/drivers/gpu/drm/amd/display/dc/dml/dcn21/display_mode_vba_21.c
@@ -841,6 +841,9 @@ static bool CalculatePrefetchSchedule(
else
*DestinationLinesForPrefetch = dst_y_prefetch_equ;
+ // Limit to prevent overflow in DST_Y_PREFETCH register
+ *DestinationLinesForPrefetch = dml_min(*DestinationLinesForPrefetch, 63.75);
+
dml_print("DML: VStartup: %d\n", VStartup);
dml_print("DML: TCalc: %f\n", TCalc);
dml_print("DML: TWait: %f\n", TWait);