From 14e96b4ef1f76926a3d9c1c4821266f3f81e6c14 Mon Sep 17 00:00:00 2001 From: Terry Cheong Date: Tue, 25 Nov 2025 16:29:56 +0800 Subject: [PATCH] mb/google/brox/caboc: Mute speaker amp to prevent pop noise on reboot A pop noise is heard from the speakers on caboc devices when rebooting while audio is playing. This is caused by the speaker amplifier (class-D) being active during the reboot process. This change mutes the amplifier by updating the HDA verb table, which is configured at boot time. The amplifier will be unmuted when generating a dev beep to preserve that functionality. BUG=b:439638686 TEST=Play audio in the OS and reboot the device. Verify that no pop noise is heard from the speakers. Change-Id: Ic9980d31097d60ede879c8d6dcdd541580765795 Signed-off-by: Terry Cheong Reviewed-on: https://review.coreboot.org/c/coreboot/+/90199 Reviewed-by: Eric Lai Tested-by: build bot (Jenkins) --- .../google/brox/variants/caboc/include/variant/hda_verb.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/mainboard/google/brox/variants/caboc/include/variant/hda_verb.h b/src/mainboard/google/brox/variants/caboc/include/variant/hda_verb.h index e6b4d057bf..3edbe5e39e 100644 --- a/src/mainboard/google/brox/variants/caboc/include/variant/hda_verb.h +++ b/src/mainboard/google/brox/variants/caboc/include/variant/hda_verb.h @@ -128,7 +128,7 @@ const u32 pc_beep_verbs[] = { 0x02050010, 0x02040320, /* Dos beep path - 2 */ - 0x0143B000, + 0x0143B080, 0x01470740, 0x01470C02, 0x01470C02,