drm/amd/display: Force det buf size to 192KB with 3+ streams and upscaling

[WHY]
This workaround resolves underflow caused by incorrect DST_Y_PREFETCH.
Overriding to 192KB DET buf size until the DST_Y_PREFETCH calc is fixed.

Reviewed-by: Eric Yang <Eric.Yang2@amd.com>
Acked-by: Pavle Kotarac <Pavle.Kotarac@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Michael Strauss <michael.strauss@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
index ff93f29..29ee3c2 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
@@ -1776,6 +1776,7 @@ static int dcn31_populate_dml_pipes_from_context(
        int i, pipe_cnt;
        struct resource_context *res_ctx = &context->res_ctx;
        struct pipe_ctx *pipe;
+       bool upscaled = false;
 
        dcn20_populate_dml_pipes_from_context(dc, context, pipes, fast_validate);
 
@@ -1787,6 +1788,11 @@ static int dcn31_populate_dml_pipes_from_context(
                pipe = &res_ctx->pipe_ctx[i];
                timing = &pipe->stream->timing;
 
+               if (pipe->plane_state &&
+                               (pipe->plane_state->src_rect.height < pipe->plane_state->dst_rect.height ||
+                               pipe->plane_state->src_rect.width < pipe->plane_state->dst_rect.width))
+                       upscaled = true;
+
                /*
                 * Immediate flip can be set dynamically after enabling the plane.
                 * We need to require support for immediate flip or underflow can be
@@ -1834,6 +1840,8 @@ static int dcn31_populate_dml_pipes_from_context(
        } else if (context->stream_count >= dc->debug.crb_alloc_policy_min_disp_count
                        && dc->debug.crb_alloc_policy > DET_SIZE_DEFAULT) {
                context->bw_ctx.dml.ip.det_buffer_size_kbytes = dc->debug.crb_alloc_policy * 64;
+       } else if (context->stream_count >= 3 && upscaled) {
+               context->bw_ctx.dml.ip.det_buffer_size_kbytes = 192;
        }
 
        return pipe_cnt;