This is a note to let you know that I've just added the patch titled
drm/vc4: hdmi: Avoid full hdmi audio fifo writes
to the 5.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-vc4-hdmi-avoid-full-hdmi-audio-fifo-writes.patch
and it can be found in the queue-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6c7bc407578b9207d8ea18915e5c19f88adf1302
Author: Dom Cobley <popcornmix@xxxxxxxxx>
Date: Mon Jun 13 16:47:47 2022 +0200
drm/vc4: hdmi: Avoid full hdmi audio fifo writes
[ Upstream commit 1c594eeccf92368177c2e22f1d3ee4933dfb8567 ]
We are getting occasional VC4_HD_MAI_CTL_ERRORF in
HDMI_MAI_CTL which seem to correspond with audio dropouts.
Reduce the threshold where we deassert DREQ to avoid the fifo
overfilling
Fixes: bb7d78568814 ("drm/vc4: Add HDMI audio support")
Signed-off-by: Dom Cobley <popcornmix@xxxxxxxxx>
Link: https://lore.kernel.org/r/20220613144800.326124-21-maxime@xxxxxxxxxx
Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index ecd49214bd92..d0921f832f19 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -1956,10 +1956,10 @@ static int vc4_hdmi_audio_prepare(struct device *dev, void *data,
/* 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));
+ VC4_SET_FIELD(0x08, VC4_HD_MAI_THR_PANICHIGH) |
+ VC4_SET_FIELD(0x08, VC4_HD_MAI_THR_PANICLOW) |
+ VC4_SET_FIELD(0x06, VC4_HD_MAI_THR_DREQHIGH) |
+ VC4_SET_FIELD(0x08, VC4_HD_MAI_THR_DREQLOW));
HDMI_WRITE(HDMI_MAI_CONFIG,
VC4_HDMI_MAI_CONFIG_BIT_REVERSE |
