[PATCH AUTOSEL 6.0 39/73] drm/amd/display: Workaround to increase phantom pipe vactive in pipesplit

Sasha Levin
2022-12-18T16:28:21Z

From: George Shen <george.shen@amd.com>

[ Upstream commit 5b8f9deaf3b6badfc0da968e6e07ceabd19700b6 ]

[Why]
Certain high resolution displays exhibit DCC line corruption with SubVP
enabled. This is likely due to insufficient DCC meta data buffered
immediately after the mclk switch.

[How]
Add workaround to increase phantom pipe vactive height by
meta_row_height number of lines, thus increasing the amount of meta data
buffered immediately after mclk switch finishes.

Reviewed-by: Alvin Lee <Alvin.Lee2@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: George Shen <george.shen@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@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/dml/dcn32/dcn32_fpu.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c b/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
index 07c56e231b04..d05df4f7139f 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
+++ b/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
@@ -485,9 +485,11 @@ void dcn32_set_phantom_stream_timing(struct dc *dc,
unsigned int i, pipe_idx;
struct pipe_ctx *pipe;
uint32_t phantom_vactive, phantom_bp, pstate_width_fw_delay_lines;
+ unsigned int num_dpp;
unsigned int vlevel = context->bw_ctx.dml.vba.VoltageLevel;
unsigned int dcfclk = context->bw_ctx.dml.vba.DCFCLKState[vlevel][context->bw_ctx.dml.vba.maxMpcComb];
unsigned int socclk = context->bw_ctx.dml.vba.SOCCLKPerState[vlevel];
+ struct vba_vars_st *vba = &context->bw_ctx.dml.vba;

dc_assert_fp_enabled();

@@ -523,6 +525,11 @@ void dcn32_set_phantom_stream_timing(struct dc *dc,
phantom_vactive = get_subviewport_lines_needed_in_mall(&context->bw_ctx.dml, pipes, pipe_cnt, pipe_idx) +
pstate_width_fw_delay_lines + dc->caps.subvp_swath_height_margin_lines;

+ // W/A for DCC corruption with certain high resolution timings.
+ // Determing if pipesplit is used. If so, add meta_row_height to the phantom vactive.
+ num_dpp = vba->NoOfDPP[vba->VoltageLevel][vba->maxMpcComb][vba->pipe_plane[pipe_idx]];
+ phantom_vactive += num_dpp > 1 ? vba->meta_row_height[vba->pipe_plane[pipe_idx]] : 0;
+
// For backporch of phantom pipe, use vstartup of the main pipe
phantom_bp = get_vstartup(&context->bw_ctx.dml, pipes, pipe_cnt, pipe_idx);

--
2.35.1