From bfeda4f2ad474af6938c9daf0af39961379167da Mon Sep 17 00:00:00 2001
From: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Date: Wed, 7 Sep 2022 10:11:34 -0400
Subject: drm/amd/display: Do DIO FIFO enable after DP video stream enable
Git-commit: d3d61281edc0ab0c3d566e760d5bd4db5a9c217a
Patch-mainline: v6.1-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225 jsc#PED-2849
[Why]
Avoids a race condition where DIO FIFO can underflow due to no incoming
data available.
[How]
Shift the FIFO enable below stream enable.
Make sure fullness level is written before the DIO reset takes place
and that we're not doing it twice.
Reviewed-by: Syed Hassan <Syed.Hassan@amd.com>
Acked-by: Jasdeep Dhillon <jdhillon@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
.../gpu/drm/amd/display/dc/dcn314/dcn314_dio_stream_encoder.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_dio_stream_encoder.c b/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_dio_stream_encoder.c
index eb5472d7523c..0d2ffb692957 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_dio_stream_encoder.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_dio_stream_encoder.c
@@ -327,7 +327,6 @@ static void enc314_stream_encoder_dp_unblank(
/* switch DP encoder to CRTC data, but reset it the fifo first. It may happen
* that it overflows during mode transition, and sometimes doesn't recover.
*/
- REG_UPDATE(DIG_FIFO_CTRL0, DIG_FIFO_READ_START_LEVEL, 0x7);
REG_UPDATE(DP_STEER_FIFO, DP_STEER_FIFO_RESET, 1);
udelay(10);
--
2.38.1