From c69a53be3b5f6f7cba0ac6a5461d4f342f7e9c41 Mon Sep 17 00:00:00 2001 From: Dom Cobley Date: Tue, 23 Jun 2020 18:37:01 +0100 Subject: [PATCH] vc4_hdmi: Set HD_CTL_WHOLSMP and HD_CTL_CHALIGN_SET 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 --- drivers/gpu/drm/vc4/vc4_hdmi.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -1002,6 +1002,8 @@ static int vc4_hdmi_audio_trigger(struct HDMI_WRITE(HDMI_MAI_CTL, VC4_SET_FIELD(vc4_hdmi->audio.channels, VC4_HD_MAI_CTL_CHNUM) | + VC4_HD_MAI_CTL_WHOLSMP | + VC4_HD_MAI_CTL_CHALIGN | VC4_HD_MAI_CTL_ENABLE); break; case SNDRV_PCM_TRIGGER_STOP: