target/linux/bcm27xx/patches-5.10/950-0505-vc4-drm-Avoid-full-hdmi-audio-fifo-writes.patch

   1 From d0df79e13ab947367b86d7861e34f85aa6aad020 Mon Sep 17 00:00:00 2001
   2 From: Dom Cobley <popcornmix@gmail.com>
   3 Date: Sun, 24 Jan 2021 15:44:10 +0000
   4 Subject: [PATCH] vc4/drm: Avoid full hdmi audio fifo writes
   5
   6 We are getting occasional VC4_HD_MAI_CTL_ERRORF in
   7 HDMI_MAI_CTL which seem to correspond with audio dropouts.
   8
   9 Reduce the threshold where we deassert DREQ to avoid the fifo overfilling
  10
  11 Signed-off-by: Dom Cobley <popcornmix@gmail.com>
  12 ---
  13  drivers/gpu/drm/vc4/vc4_hdmi.c | 8 ++++----
  14  1 file changed, 4 insertions(+), 4 deletions(-)
  15
  16 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
  17 +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
  18 @@ -1294,10 +1294,10 @@ static int vc4_hdmi_audio_prepare(struct
  19
  20         /* Set the MAI threshold */
  21         HDMI_WRITE(HDMI_MAI_THR,
  22 -                  VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_PANICHIGH) |
  23 -                  VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_PANICLOW) |
  24 -                  VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_DREQHIGH) |
  25 -                  VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_DREQLOW));
  26 +                  VC4_SET_FIELD(0x08, VC4_HD_MAI_THR_PANICHIGH) |
  27 +                  VC4_SET_FIELD(0x08, VC4_HD_MAI_THR_PANICLOW) |
  28 +                  VC4_SET_FIELD(0x06, VC4_HD_MAI_THR_DREQHIGH) |
  29 +                  VC4_SET_FIELD(0x08, VC4_HD_MAI_THR_DREQLOW));
  30
  31         HDMI_WRITE(HDMI_MAI_CONFIG,
  32                    VC4_HDMI_MAI_CONFIG_BIT_REVERSE |