[coreboot-gerrit] [S] Change in coreboot[main]: mb/google/nissa/var/teliks: Force audio mute to avoid screen flick

[Jianeng Ceng (Code Review)]

Jianeng Ceng has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/84137?usp=email )

Change subject: mb/google/nissa/var/teliks: Force audio mute to avoid screen flick
......................................................................

mb/google/nissa/var/teliks: Force audio mute to avoid screen flick

Panel CSOT MNB601LS1-3 will flicker once during enter Chrome login
screen, it is because it inserts 12 blank frames if it receives the
unmute in VB-ID.

Always override the mute in VB-ID to avoid Tcon EC detected the
audiomute_flag change.

BUG:b=360243615
BRANCH=firmware-nissa-15217.B
TEST:Verfied on Teliks and cannot reproduce the issue

Change-Id: Iff488f6844c717ef24069c7176e7b8dfb07d8abc
Signed-off-by: Jianeng Ceng 
---
M src/mainboard/google/brya/variants/teliks/variant.c
1 file changed, 18 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/37/84137/1

diff --git a/src/mainboard/google/brya/variants/teliks/variant.c b/src/mainboard/google/brya/variants/teliks/variant.c
index 7cc4af8..3f7cfd6 100644
--- a/src/mainboard/google/brya/variants/teliks/variant.c
+++ b/src/mainboard/google/brya/variants/teliks/variant.c
@@ -5,6 +5,11 @@
 #include <fw_config.h>
 #include <sar.h>
 #include <soc/gpio_soc_defs.h>
+#include <intelblocks/graphics.h>
+
+/* Per-pipe DDI Function Control 2 */
+#define TRANS_DDI_FUNC_CTL2_A					0x60404
+#define TRANS_DDI_AUDIO_MUTE_OVERRIDE_BITS_FIELDS		(3 << 6)

const char *get_wifi_sar_cbfs_filename(void)
 {
@@ -36,3 +41,16 @@
    					ARRAY_SIZE(wifi_pcie_enable_pad));
    }
 }
+
+void variant_finalize(void)
+{
+	/*
+	 * Panel CSOT MNB601LS1-3 will flicker once during enter Chrome login screen,
+	 * it is because it inserts 12 blank frames if it receives the unmute in VB-ID.
+	 *
+	 * Always override the mute in VB-ID to avoid Tcon EC detected the
+	 * audiomute_flag change.
+	 */
+	graphics_gtt_rmw(TRANS_DDI_FUNC_CTL2_A, ~TRANS_DDI_AUDIO_MUTE_OVERRIDE_BITS_FIELDS,
+		TRANS_DDI_AUDIO_MUTE_OVERRIDE_BITS_FIELDS);
+}