Patch "drm/amd/display: fix dcn315 single stream crb allocation" has been added to the 6.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/amd/display: fix dcn315 single stream crb allocation

to the 6.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-amd-display-fix-dcn315-single-stream-crb-allocat.patch
and it can be found in the queue-6.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit bfaca573c34e5c1632c7d88930ef4067d398f550
Author: Dmytro Laktyushkin <dmytro.laktyushkin@xxxxxxx>
Date:   Tue May 16 15:50:40 2023 -0400

    drm/amd/display: fix dcn315 single stream crb allocation
    
    [ Upstream commit 49f26218c344741cb3eaa740b1e44e960551a87f ]
    
    Change to improve avoiding asymetric crb calculations for single stream
    scenarios.
    
    Cc: Mario Limonciello <mario.limonciello@xxxxxxx>
    Cc: Alex Deucher <alexander.deucher@xxxxxxx>
    Cc: stable@xxxxxxxxxxxxxxx
    Acked-by: Stylon Wang <stylon.wang@xxxxxxx>
    Signed-off-by: Dmytro Laktyushkin <dmytro.laktyushkin@xxxxxxx>
    Reviewed-by: Charlene Liu <Charlene.Liu@xxxxxxx>
    Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
    Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/amd/display/dc/dcn315/dcn315_resource.c b/drivers/gpu/drm/amd/display/dc/dcn315/dcn315_resource.c
index 42a0157fd8133..ae99b2851e019 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn315/dcn315_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn315/dcn315_resource.c
@@ -1662,6 +1662,10 @@ static bool allow_pixel_rate_crb(struct dc *dc, struct dc_state *context)
 	int i;
 	struct resource_context *res_ctx = &context->res_ctx;
 
+	/*Don't apply for single stream*/
+	if (context->stream_count < 2)
+		return false;
+
 	for (i = 0; i < dc->res_pool->pipe_count; i++) {
 		if (!res_ctx->pipe_ctx[i].stream)
 			continue;
@@ -1748,19 +1752,23 @@ static int dcn315_populate_dml_pipes_from_context(
 		pipe_cnt++;
 	}
 
-	/* Spread remaining unreserved crb evenly among all pipes, use default policy if not enough det or single pipe */
+	/* Spread remaining unreserved crb evenly among all pipes*/
 	if (pixel_rate_crb) {
 		for (i = 0, pipe_cnt = 0, crb_idx = 0; i < dc->res_pool->pipe_count; i++) {
 			pipe = &res_ctx->pipe_ctx[i];
 			if (!pipe->stream)
 				continue;
 
+			/* Do not use asymetric crb if not enough for pstate support */
+			if (remaining_det_segs < 0) {
+				pipes[pipe_cnt].pipe.src.det_size_override = 0;
+				continue;
+			}
+
 			if (!pipe->top_pipe && !pipe->prev_odm_pipe) {
 				bool split_required = pipe->stream->timing.pix_clk_100hz >= dcn_get_max_non_odm_pix_rate_100hz(&dc->dml.soc)
 						|| (pipe->plane_state && pipe->plane_state->src_rect.width > 5120);
 
-				if (remaining_det_segs < 0 || crb_pipes == 1)
-					pipes[pipe_cnt].pipe.src.det_size_override = 0;
 				if (remaining_det_segs > MIN_RESERVED_DET_SEGS)
 					pipes[pipe_cnt].pipe.src.det_size_override += (remaining_det_segs - MIN_RESERVED_DET_SEGS) / crb_pipes +
 							(crb_idx < (remaining_det_segs - MIN_RESERVED_DET_SEGS) % crb_pipes ? 1 : 0);
@@ -1776,6 +1784,7 @@ static int dcn315_populate_dml_pipes_from_context(
 				}
 				/* Convert segments into size for DML use */
 				pipes[pipe_cnt].pipe.src.det_size_override *= DCN3_15_CRB_SEGMENT_SIZE_KB;
+
 				crb_idx++;
 			}
 			pipe_cnt++;