diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-5.10/950-0317-vc4_hdmi-Remove-firmware-logic-for-MAI-threshold-set.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-5.10/950-0317-vc4_hdmi-Remove-firmware-logic-for-MAI-threshold-set.patch | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-5.10/950-0317-vc4_hdmi-Remove-firmware-logic-for-MAI-threshold-set.patch b/target/linux/bcm27xx/patches-5.10/950-0317-vc4_hdmi-Remove-firmware-logic-for-MAI-threshold-set.patch new file mode 100644 index 0000000000..96b5456d4b --- /dev/null +++ b/target/linux/bcm27xx/patches-5.10/950-0317-vc4_hdmi-Remove-firmware-logic-for-MAI-threshold-set.patch @@ -0,0 +1,47 @@ +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 | |