[PATCH AUTOSEL 5.7 095/274] drm/amd/display: Revert to old formula in set_vtg_params

Sasha Levin
2020-06-09T01:00:56Z

From: Alvin Lee <alvin.lee2@amd.com>

[ Upstream commit a1a0e61f3c43c610f0a3c109348c14ce930c1977 ]

[Why]
New formula + cursor change causing underflow
on certain configs

[How]
Rever to old formula

Signed-off-by: Alvin Lee <alvin.lee2@amd.com>
Reviewed-by: Yongqiang Sun <yongqiang.sun@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c
index 17d96ec6acd8..ec0ab42becba 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c
@@ -299,6 +299,7 @@ void optc1_set_vtg_params(struct timing_generator *optc,
uint32_t asic_blank_end;
uint32_t v_init;
uint32_t v_fp2 = 0;
+ int32_t vertical_line_start;

struct optc *optc1 = DCN10TG_FROM_TG(optc);

@@ -315,8 +316,9 @@ void optc1_set_vtg_params(struct timing_generator *optc,
patched_crtc_timing.v_border_top;

/* if VSTARTUP is before VSYNC, FP2 is the offset, otherwise 0 */
- if (optc1->vstartup_start > asic_blank_end)
- v_fp2 = optc1->vstartup_start - asic_blank_end;
+ vertical_line_start = asic_blank_end - optc1->vstartup_start + 1;
+ if (vertical_line_start < 0)
+ v_fp2 = -vertical_line_start;

/* Interlace */
if (REG(OTG_INTERLACE_CONTROL)) {
--
2.25.1