From acaf72ab5a171a8199dd950967bcbdc47007e7bf Mon Sep 17 00:00:00 2001
From: Dom Cobley <popcornmix@gmail.com>
Date: Tue, 25 May 2021 15:23:51 +0200
Subject: drm/vc4: hdmi: Remove firmware logic for MAI threshold setting
Git-commit: 8434111ccfec8fc0549ec325a632067232d38e14
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
This was a workaround for bugs in hardware on earlier Pi models
and wasn't totally successful.
It makes audio quality worse on a Pi4 at the higher sample rates
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20210525132354.297468-10-maxime@cerno.tech
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/vc4/vc4_hdmi.c | 22 ++++++----------------
1 file changed, 6 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 76fa09303ec2..fecfda790c83 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -1374,22 +1374,12 @@ static int vc4_hdmi_audio_hw_params(struct snd_pcm_substream *substream,
audio_packet_config |= VC4_SET_FIELD(channel_mask,
VC4_HDMI_AUDIO_PACKET_CEA_MASK);
- /* Set the MAI threshold. This logic mimics the firmware's. */
- if (vc4_hdmi->audio.samplerate > 96000) {
- HDMI_WRITE(HDMI_MAI_THR,
- VC4_SET_FIELD(0x12, VC4_HD_MAI_THR_DREQHIGH) |
- VC4_SET_FIELD(0x12, VC4_HD_MAI_THR_DREQLOW));
- } else if (vc4_hdmi->audio.samplerate > 48000) {
- HDMI_WRITE(HDMI_MAI_THR,
- VC4_SET_FIELD(0x14, VC4_HD_MAI_THR_DREQHIGH) |
- VC4_SET_FIELD(0x12, VC4_HD_MAI_THR_DREQLOW));
- } else {
- HDMI_WRITE(HDMI_MAI_THR,
- VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_PANICHIGH) |
- VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_PANICLOW) |
- VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_DREQHIGH) |
- VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_DREQLOW));
- }
+ /* Set the MAI threshold */
+ HDMI_WRITE(HDMI_MAI_THR,
+ VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_PANICHIGH) |
+ VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_PANICLOW) |
+ VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_DREQHIGH) |
+ VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_DREQLOW));
HDMI_WRITE(HDMI_MAI_CONFIG,
VC4_HDMI_MAI_CONFIG_BIT_REVERSE |
--
2.38.1