drm/amd/display: Write flip addr to scratch reg for subvp

[Description]
SubVP needs to "calculate" the earliest in use META address
by using the current primary / meta addresses, but this leads
to a race condition where FW and driver can read/write the
address at the same time and intermittently produce inconsistent
address offsets. To mitigate this issue without locking (too slow),
save each surface flip addr into scratch registers and use this
to keep track of the earliest in use META addres.

Reviewed-by: Jun Lei <jun.lei@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Alvin Lee <alvin.lee2@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
index 65fa9e21ad9c..d3caba52d2fc 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
@@ -1679,8 +1679,18 @@ static void dcn20_update_dchubp_dpp(
 
 	if (pipe_ctx->update_flags.bits.enable ||
 		pipe_ctx->update_flags.bits.plane_changed ||
-		plane_state->update_flags.bits.addr_update)
+		plane_state->update_flags.bits.addr_update) {
+		if (resource_is_pipe_type(pipe_ctx, OTG_MASTER) &&
+				pipe_ctx->stream->mall_stream_config.type == SUBVP_MAIN) {
+			union block_sequence_params params;
+
+			params.subvp_save_surf_addr.dc_dmub_srv = dc->ctx->dmub_srv;
+			params.subvp_save_surf_addr.addr = &pipe_ctx->plane_state->address;
+			params.subvp_save_surf_addr.subvp_index = pipe_ctx->subvp_index;
+			hwss_subvp_save_surf_addr(&params);
+		}
 		hws->funcs.update_plane_addr(dc, pipe_ctx);
+	}
 
 	if (pipe_ctx->update_flags.bits.enable)
 		hubp->funcs->set_blank(hubp, false);