From 6b0703f4c5cbf87d5e51c90e496f20e0314c8fae Mon Sep 17 00:00:00 2001
From: Dom Cobley <popcornmix@gmail.com>
Date: Tue, 25 May 2021 15:23:48 +0200
Subject: drm/vc4: hdmi: Set HD_CTL_WHOLSMP and HD_CTL_CHALIGN_SET
Git-commit: 1698ecb218eb82587dbfc71a2e26ded66e5ecf59
Patch-mainline: v5.15-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
Symptom is random switching of speakers when using multichannel.
Repeatedly running speakertest -c8 occasionally starts with
channels jumbled. This is fixed with HD_CTL_WHOLSMP.
The other bit looks beneficial and apears harmless in testing so
I'd suggest adding it too.
Documentation says: HD_CTL_WHILSMP_SET
Wait for whole sample. When this bit is set MAI transmit will start
only when there is at least one whole sample available in the fifo.
Documentation says: HD_CTL_CHALIGN_SET
Channel Align When Overflow. This bit is used to realign the audio
channels in case of an overflow.
If this bit is set, after the detection of an overflow, equal
amount of dummy words to the missing words will be written to fifo,
filling up the broken sample and maintaining alignment.
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210525132354.297468-7-maxime@cerno.tech
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/vc4/vc4_hdmi.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index b921fad391d2..1ab1b322d201 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -1372,7 +1372,9 @@ static int vc4_hdmi_audio_trigger(struct snd_pcm_substream *substream, int cmd,
HDMI_WRITE(HDMI_MAI_CTL,
VC4_SET_FIELD(vc4_hdmi->audio.channels,
VC4_HD_MAI_CTL_CHNUM) |
- VC4_HD_MAI_CTL_ENABLE);
+ VC4_HD_MAI_CTL_WHOLSMP |
+ VC4_HD_MAI_CTL_CHALIGN |
+ VC4_HD_MAI_CTL_ENABLE);
break;
case SNDRV_PCM_TRIGGER_STOP:
HDMI_WRITE(HDMI_MAI_CTL,
--
2.38.1