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 6.8-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-calculation.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 719564737a9ac3d0b49c314450b56cf6f7d71358 Mon Sep 17 00:00:00 2001
From: George Shen <george.shen@xxxxxxx>
Date: Thu, 16 Sep 2021 19:55:39 -0400
Subject: drm/amd/display: Handle Y carry-over in VCP X.Y calculation
From: George Shen <george.shen@xxxxxxx>
commit 719564737a9ac3d0b49c314450b56cf6f7d71358 upstream.
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.
CC: stable@xxxxxxxxxxxxxxx
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/amd/display/dc/dcn31/dcn31_hpo_dp_link_encoder.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_hpo_dp_link_encoder.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_hpo_dp_link_encoder.c
@@ -395,6 +395,12 @@ void dcn31_hpo_dp_link_enc_set_throttled
x),
25));
+ // If y rounds up to integer, carry it over to x.
+ if (y >> 25) {
+ x += 1;
+ y = 0;
+ }
+
switch (stream_encoder_inst) {
case 0:
REG_SET_2(DP_DPHY_SYM32_VC_RATE_CNTL0, 0,
Patches currently in stable-queue which might be from george.shen@xxxxxxx are
queue-6.8/drm-amd-display-handle-y-carry-over-in-vcp-x.y-calculation.patch
