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mb/google/brox/caboc: Mute speaker amp to prevent pop noise on reboot

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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 <htcheong@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/90199
Reviewed-by: Eric Lai <ericllai@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
This commit is contained in:
Terry Cheong 2025-11-25 16:29:56 +08:00 • committed by Matt DeVillier
commit 14e96b4ef1
1 changed files with 1 additions and 1 deletions
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2
src/mainboard/google/brox/variants/caboc/include/variant/hda_verb.h
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@ -128,7 +128,7 @@ const u32 pc_beep_verbs[] = {
0x02050010,
0x02040320,
/* Dos beep path - 2 */
0x0143B000,
0x0143B080,
0x01470740,
0x01470C02,
0x01470C02,