[PATCH 06/37] drm/amd/display: Handle Y carry-over in VCP X.Y calculation

[Aurabindo Pillai]

From: George Shen <george.s...@amd.com>

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: sta...@vger.kernel.org
Reviewed-by: Rodrigo Siqueira <rodrigo.sique...@amd.com>
Signed-off-by: George Shen <george.s...@amd.com>
Tested-by: Daniel Wheeler <daniel.whee...@amd.com>
---
 .../drm/amd/display/dc/dcn31/dcn31_hpo_dp_link_encoder.c    | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git 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
index 48e63550f696..03b4ac2f1991 100644
--- 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_vcp_size(
                                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,
-- 
2.44.0