openwrt/target/linux/bcm27xx/patches-5.10/950-0317-vc4_hdmi-Remove-firmware-logic-for-MAI-threshold-set.patch
Álvaro Fernández Rojas 8299d1f057 bcm27xx: add kernel 5.10 support
Rebased RPi foundation patches on linux 5.10.59, removed applied and reverted
patches, wireless patches and defconfig patches.

bcm2708: boot tested on RPi B+ v1.2
bcm2709: boot tested on RPi 4B v1.1 4G
bcm2711: boot tested on RPi 4B v1.1 4G

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
2021-08-21 19:07:07 +02:00

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1.8 KiB
Diff

From 3c398513990aa0edc5b9ebfbdd2395623562c6e4 Mon Sep 17 00:00:00 2001
From: Dom Cobley <popcornmix@gmail.com>
Date: Thu, 25 Jun 2020 18:48:40 +0100
Subject: [PATCH] vc4_hdmi: Remove firmware logic for MAI threshold
setting
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>
---
drivers/gpu/drm/vc4/vc4_hdmi.c | 22 ++++++----------------
1 file changed, 6 insertions(+), 16 deletions(-)
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -1083,22 +1083,12 @@ static int vc4_hdmi_audio_prepare(struct
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 |