48 lines
1.8 KiB
Diff
48 lines
1.8 KiB
Diff
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From 3c398513990aa0edc5b9ebfbdd2395623562c6e4 Mon Sep 17 00:00:00 2001
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From: Dom Cobley <popcornmix@gmail.com>
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Date: Thu, 25 Jun 2020 18:48:40 +0100
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Subject: [PATCH] vc4_hdmi: Remove firmware logic for MAI threshold
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setting
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This was a workaround for bugs in hardware on earlier Pi models
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and wasn't totally successful.
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It makes audio quality worse on a Pi4 at the higher sample rates
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Signed-off-by: Dom Cobley <popcornmix@gmail.com>
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---
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drivers/gpu/drm/vc4/vc4_hdmi.c | 22 ++++++----------------
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1 file changed, 6 insertions(+), 16 deletions(-)
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--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
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+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
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@@ -1083,22 +1083,12 @@ static int vc4_hdmi_audio_prepare(struct
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audio_packet_config |= VC4_SET_FIELD(channel_mask,
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VC4_HDMI_AUDIO_PACKET_CEA_MASK);
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- /* Set the MAI threshold. This logic mimics the firmware's. */
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- if (vc4_hdmi->audio.samplerate > 96000) {
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- HDMI_WRITE(HDMI_MAI_THR,
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- VC4_SET_FIELD(0x12, VC4_HD_MAI_THR_DREQHIGH) |
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- VC4_SET_FIELD(0x12, VC4_HD_MAI_THR_DREQLOW));
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- } else if (vc4_hdmi->audio.samplerate > 48000) {
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- HDMI_WRITE(HDMI_MAI_THR,
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- VC4_SET_FIELD(0x14, VC4_HD_MAI_THR_DREQHIGH) |
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- VC4_SET_FIELD(0x12, VC4_HD_MAI_THR_DREQLOW));
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- } else {
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- HDMI_WRITE(HDMI_MAI_THR,
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- VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_PANICHIGH) |
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- VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_PANICLOW) |
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- VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_DREQHIGH) |
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- VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_DREQLOW));
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- }
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+ /* Set the MAI threshold */
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+ HDMI_WRITE(HDMI_MAI_THR,
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+ VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_PANICHIGH) |
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+ VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_PANICLOW) |
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+ VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_DREQHIGH) |
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+ VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_DREQLOW));
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HDMI_WRITE(HDMI_MAI_CONFIG,
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VC4_HDMI_MAI_CONFIG_BIT_REVERSE |
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