From 0d940daa7296f57b59a9efbd8515b9032fe8f1f2 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Mon, 28 Mar 2022 17:36:55 +0200
Subject: drm/vc4: txp: Don't set TXP_VSTART_AT_EOF
Git-commit: 234998df929f14d00cbf2f1e81a7facb69fd9266
Patch-mainline: v5.19-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
The TXP_VSTART_AT_EOF will generate a second VSTART signal to the HVS.
However, the HVS waits for VSTART to enable the FIFO and will thus start
filling the FIFO before the start of the frame.
This leads to corruption at the beginning of the first frame, and
content from the previous frame at the beginning of the next frames.
Since one VSTART is enough, let's get rid of it.
Fixes: 008095e065a8 ("drm/vc4: Add support for the transposer block")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://lore.kernel.org/r/20220328153659.2382206-3-maxime@cerno.tech
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/vc4/vc4_txp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/vc4/vc4_txp.c b/drivers/gpu/drm/vc4/vc4_txp.c
index 9809ca3e2945..ace2d03649ba 100644
--- a/drivers/gpu/drm/vc4/vc4_txp.c
+++ b/drivers/gpu/drm/vc4/vc4_txp.c
@@ -298,7 +298,7 @@ static void vc4_txp_connector_atomic_commit(struct drm_connector *conn,
if (WARN_ON(i == ARRAY_SIZE(drm_fmts)))
return;
- ctrl = TXP_GO | TXP_VSTART_AT_EOF | TXP_EI |
+ ctrl = TXP_GO | TXP_EI |
VC4_SET_FIELD(0xf, TXP_BYTE_ENABLE) |
VC4_SET_FIELD(txp_fmts[i], TXP_FORMAT);
--
2.38.1