This is a note to let you know that I've just added the patch titled
drm/amd/display: Handle Y carry-over in VCP X.Y calculation
to the 4.19-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-handle-y-carry-over-in-vcp-x.y-calcu.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 337fade8785b1ccaadc4fdac9883f27d59327b09
Author: George Shen <george.shen@xxxxxxx>
Date: Thu Sep 16 19:55:39 2021 -0400
drm/amd/display: Handle Y carry-over in VCP X.Y calculation
[ Upstream commit 3626a6aebe62ce7067cdc460c0c644e9445386bb ]
[Why/How]
Theoretically rare corner case where ceil(Y) results in rounding
up to an integer. If this happens, the 1 should be carried over to
the X value.
Reviewed-by: Wenjing Liu <wenjing.liu@xxxxxxx>
Acked-by: Anson Jacob <Anson.Jacob@xxxxxxx>
Signed-off-by: George Shen <george.shen@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/dcn10/dcn10_stream_encoder.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.c
index 6f9078f3c4d39..17bcf7ce4099c 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.c
@@ -620,6 +620,12 @@ void enc1_stream_encoder_set_mst_bandwidth(
x),
26));
+ // If y rounds up to integer, carry it over to x.
+ if (y >> 26) {
+ x += 1;
+ y = 0;
+ }
+
REG_SET_2(DP_MSE_RATE_CNTL, 0,
DP_MSE_RATE_X, x,
DP_MSE_RATE_Y, y);
