From 7e20a732364c4c06753d14cc72e376f7be245cd2 Mon Sep 17 00:00:00 2001 From: Lo-an Chen Date: Wed, 12 Mar 2025 22:51:00 +0900 Subject: [PATCH] drm/amd/display: Correct prefetch calculation BugLink: https://bugs.launchpad.net/bugs/2102118 commit 24d3749c11d949972d8c22e75567dc90ff5482e7 upstream. [WHY] The minimum value of the dst_y_prefetch_equ was not correct in prefetch calculation whice causes OPTC underflow. [HOW] Add the min operation of dst_y_prefetch_equ in prefetch calculation. Cc: Mario Limonciello Cc: Alex Deucher Cc: stable@vger.kernel.org Reviewed-by: Nicholas Kazlauskas Signed-off-by: Lo-an Chen Signed-off-by: Alex Hung Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Signed-off-by: Greg Kroah-Hartman Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c b/drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c index 85ffad564ed0..aa3fa0a9d934 100644 --- a/drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c +++ b/drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c @@ -1219,6 +1219,7 @@ static dml_bool_t CalculatePrefetchSchedule(struct display_mode_lib_scratch_st * s->dst_y_prefetch_oto = s->Tvm_oto_lines + 2 * s->Tr0_oto_lines + s->Lsw_oto; s->dst_y_prefetch_equ = p->VStartup - (*p->TSetup + dml_max(p->TWait + p->TCalc, *p->Tdmdl)) / s->LineTime - (*p->DSTYAfterScaler + (dml_float_t) *p->DSTXAfterScaler / (dml_float_t)p->myPipe->HTotal); + s->dst_y_prefetch_equ = dml_min(s->dst_y_prefetch_equ, 63.75); // limit to the reg limit of U6.2 for DST_Y_PREFETCH #ifdef __DML_VBA_DEBUG__ dml_print("DML::%s: HTotal = %u\n", __func__, p->myPipe->HTotal);