From 9848b1e8b48e118b04b8438f12e7101c41f321c5 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: dd37fba90e72a48998d9f0eb5497088ea2b02ad1
Patch-mainline: v6.0
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>
---
.../display/dc/dcn314/dcn314_dio_stream_encoder.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
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 06d8638db696..52b71b2fef67 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
@@ -56,7 +56,8 @@ static void enc314_enable_fifo(struct stream_encoder *enc)
/* TODO: Confirm if we need to wait for DIG_SYMCLK_FE_ON */
REG_WAIT(DIG_FE_CNTL, DIG_SYMCLK_FE_ON, 1, 10, 5000);
- REG_UPDATE_2(DIG_FIFO_CTRL0, DIG_FIFO_RESET, 1, DIG_FIFO_READ_START_LEVEL, 0x7);
+ REG_UPDATE(DIG_FIFO_CTRL0, DIG_FIFO_READ_START_LEVEL, 0x7);
+ REG_UPDATE(DIG_FIFO_CTRL0, DIG_FIFO_RESET, 1);
REG_WAIT(DIG_FIFO_CTRL0, DIG_FIFO_RESET_DONE, 1, 10, 5000);
REG_UPDATE(DIG_FIFO_CTRL0, DIG_FIFO_RESET, 0);
REG_WAIT(DIG_FIFO_CTRL0, DIG_FIFO_RESET_DONE, 0, 10, 5000);
@@ -316,15 +317,11 @@ 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);
REG_UPDATE(DP_STEER_FIFO, DP_STEER_FIFO_RESET, 0);
- /* DIG Resync FIFO now needs to be explicitly enabled. */
- enc314_enable_fifo(enc);
-
/* wait 100us for DIG/DP logic to prime
* (i.e. a few video lines)
*/
@@ -340,6 +337,12 @@ static void enc314_stream_encoder_dp_unblank(
REG_UPDATE(DP_VID_STREAM_CNTL, DP_VID_STREAM_ENABLE, true);
+ /*
+ * DIG Resync FIFO now needs to be explicitly enabled.
+ * This should come after DP_VID_STREAM_ENABLE per HW docs.
+ */
+ enc314_enable_fifo(enc);
+
dp_source_sequence_trace(link, DPCD_SOURCE_SEQ_AFTER_ENABLE_DP_VID_STREAM);
}
--
2.38.1