[PATCH 08/87] drm/amd/display: cap DCFCLK hardmin to 507 for NV10

[sunpeng.li at amd.com]

From: Jun Lei <Jun.Lei at amd.com>

[why]
Due to limitation in SMU/PPLIB, it is not possible to know Fmax @ Vmin for DCFCLK.
This causes issues at high display configurations where extra headroom of DCFCLK
can enable P-state switching

[how]
Use existing override logic.  If override not defined, then force
min = 507

Signed-off-by: Jun Lei <Jun.Lei at amd.com>
Reviewed-by: Eric Yang <eric.yang2 at amd.com>
Acked-by: Leo Li <sunpeng.li at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c
index 842f48403226..d07d35a9dd0a 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c
@@ -2704,6 +2704,10 @@ static void update_bounding_box(struct dc *dc, struct _vcs_dpi_soc_bounding_box_
 
 	if (dc->bb_overrides.min_dcfclk_mhz > 0)
 		min_dcfclk = dc->bb_overrides.min_dcfclk_mhz;
+	else
+		// Accounting for SOC/DCF relationship, we can go as high as
+		// 506Mhz in Vmin.  We need to code 507 since SMU will round down to 506.
+		min_dcfclk = 507;
 
 	for (i = 0; i < num_states; i++) {
 		int min_fclk_required_by_uclk;
-- 
2.22.0