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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Wesley Chalmers <Wesley.Chalmers@amd.com>,
        Dillon Varone <Dillon.Varone@amd.com>,
        Jasdeep Dhillon <jdhillon@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
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Subject: [PATCH AUTOSEL 5.15 38/46] drm/amd/display: Use the largest vready_offset in pipe group
Date:   Sun, 18 Dec 2022 11:12:36 -0500
Message-Id: <20221218161244.930785-38-sashal@kernel.org>
In-Reply-To: <20221218161244.930785-1-sashal@kernel.org>
References: <20221218161244.930785-1-sashal@kernel.org>
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From: Wesley Chalmers <Wesley.Chalmers@amd.com>

[ Upstream commit 5842abd985b792a3b13a89b6dae4869b56656c92 ]

[WHY]
Corruption can occur in LB if vready_offset is not large enough.
DML calculates vready_offset for each pipe, but we currently select the
top pipe's vready_offset, which is not necessarily enough for all pipes
in the group.

[HOW]
Wherever program_global_sync is currently called, iterate through the
entire pipe group and find the highest vready_offset.

Reviewed-by: Dillon Varone <Dillon.Varone@amd.com>
Acked-by: Jasdeep Dhillon <jdhillon@amd.com>
Signed-off-by: Wesley Chalmers <Wesley.Chalmers@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 .../amd/display/dc/dcn10/dcn10_hw_sequencer.c | 30 +++++++++++++++++--
 .../drm/amd/display/dc/dcn20/dcn20_hwseq.c    | 29 ++++++++++++++++--
 2 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
index 91ab4dbbe1a6..c655d03ef754 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
@@ -804,6 +804,32 @@ static void false_optc_underflow_wa(
 		tg->funcs->clear_optc_underflow(tg);
 }
 
+static int calculate_vready_offset_for_group(struct pipe_ctx *pipe)
+{
+	struct pipe_ctx *other_pipe;
+	int vready_offset = pipe->pipe_dlg_param.vready_offset;
+
+	/* Always use the largest vready_offset of all connected pipes */
+	for (other_pipe = pipe->bottom_pipe; other_pipe != NULL; other_pipe = other_pipe->bottom_pipe) {
+		if (other_pipe->pipe_dlg_param.vready_offset > vready_offset)
+			vready_offset = other_pipe->pipe_dlg_param.vready_offset;
+	}
+	for (other_pipe = pipe->top_pipe; other_pipe != NULL; other_pipe = other_pipe->top_pipe) {
+		if (other_pipe->pipe_dlg_param.vready_offset > vready_offset)
+			vready_offset = other_pipe->pipe_dlg_param.vready_offset;
+	}
+	for (other_pipe = pipe->next_odm_pipe; other_pipe != NULL; other_pipe = other_pipe->next_odm_pipe) {
+		if (other_pipe->pipe_dlg_param.vready_offset > vready_offset)
+			vready_offset = other_pipe->pipe_dlg_param.vready_offset;
+	}
+	for (other_pipe = pipe->prev_odm_pipe; other_pipe != NULL; other_pipe = other_pipe->prev_odm_pipe) {
+		if (other_pipe->pipe_dlg_param.vready_offset > vready_offset)
+			vready_offset = other_pipe->pipe_dlg_param.vready_offset;
+	}
+
+	return vready_offset;
+}
+
 enum dc_status dcn10_enable_stream_timing(
 		struct pipe_ctx *pipe_ctx,
 		struct dc_state *context,
@@ -838,7 +864,7 @@ enum dc_status dcn10_enable_stream_timing(
 	pipe_ctx->stream_res.tg->funcs->program_timing(
 			pipe_ctx->stream_res.tg,
 			&stream->timing,
-			pipe_ctx->pipe_dlg_param.vready_offset,
+			calculate_vready_offset_for_group(pipe_ctx),
 			pipe_ctx->pipe_dlg_param.vstartup_start,
 			pipe_ctx->pipe_dlg_param.vupdate_offset,
 			pipe_ctx->pipe_dlg_param.vupdate_width,
@@ -2776,7 +2802,7 @@ void dcn10_program_pipe(
 
 		pipe_ctx->stream_res.tg->funcs->program_global_sync(
 				pipe_ctx->stream_res.tg,
-				pipe_ctx->pipe_dlg_param.vready_offset,
+				calculate_vready_offset_for_group(pipe_ctx),
 				pipe_ctx->pipe_dlg_param.vstartup_start,
 				pipe_ctx->pipe_dlg_param.vupdate_offset,
 				pipe_ctx->pipe_dlg_param.vupdate_width);
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 58eea3aa3bfc..bf2a8f53694b 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
@@ -1564,6 +1564,31 @@ static void dcn20_update_dchubp_dpp(
 		hubp->funcs->set_blank(hubp, false);
 }
 
+static int calculate_vready_offset_for_group(struct pipe_ctx *pipe)
+{
+	struct pipe_ctx *other_pipe;
+	int vready_offset = pipe->pipe_dlg_param.vready_offset;
+
+	/* Always use the largest vready_offset of all connected pipes */
+	for (other_pipe = pipe->bottom_pipe; other_pipe != NULL; other_pipe = other_pipe->bottom_pipe) {
+		if (other_pipe->pipe_dlg_param.vready_offset > vready_offset)
+			vready_offset = other_pipe->pipe_dlg_param.vready_offset;
+	}
+	for (other_pipe = pipe->top_pipe; other_pipe != NULL; other_pipe = other_pipe->top_pipe) {
+		if (other_pipe->pipe_dlg_param.vready_offset > vready_offset)
+			vready_offset = other_pipe->pipe_dlg_param.vready_offset;
+	}
+	for (other_pipe = pipe->next_odm_pipe; other_pipe != NULL; other_pipe = other_pipe->next_odm_pipe) {
+		if (other_pipe->pipe_dlg_param.vready_offset > vready_offset)
+			vready_offset = other_pipe->pipe_dlg_param.vready_offset;
+	}
+	for (other_pipe = pipe->prev_odm_pipe; other_pipe != NULL; other_pipe = other_pipe->prev_odm_pipe) {
+		if (other_pipe->pipe_dlg_param.vready_offset > vready_offset)
+			vready_offset = other_pipe->pipe_dlg_param.vready_offset;
+	}
+
+	return vready_offset;
+}
 
 static void dcn20_program_pipe(
 		struct dc *dc,
@@ -1582,7 +1607,7 @@ static void dcn20_program_pipe(
 
 		pipe_ctx->stream_res.tg->funcs->program_global_sync(
 				pipe_ctx->stream_res.tg,
-				pipe_ctx->pipe_dlg_param.vready_offset,
+				calculate_vready_offset_for_group(pipe_ctx),
 				pipe_ctx->pipe_dlg_param.vstartup_start,
 				pipe_ctx->pipe_dlg_param.vupdate_offset,
 				pipe_ctx->pipe_dlg_param.vupdate_width);
@@ -1875,7 +1900,7 @@ bool dcn20_update_bandwidth(
 
 			pipe_ctx->stream_res.tg->funcs->program_global_sync(
 					pipe_ctx->stream_res.tg,
-					pipe_ctx->pipe_dlg_param.vready_offset,
+					calculate_vready_offset_for_group(pipe_ctx),
 					pipe_ctx->pipe_dlg_param.vstartup_start,
 					pipe_ctx->pipe_dlg_param.vupdate_offset,
 					pipe_ctx->pipe_dlg_param.vupdate_width);
-- 
2.35.1