[PATCH 20/33] drm/vc4: hdmi: Avoid full hdmi audio fifo writes

From: Maxime Ripard <maxime@cerno.tech>
To: Daniel Vetter <daniel.vetter@intel.com>,
	David Airlie <airlied@linux.ie>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	Maxime Ripard <maxime@cerno.tech>
Cc: Dom Cobley <popcornmix@gmail.com>, dri-devel@lists.freedesktop.org
Subject: [PATCH 20/33] drm/vc4: hdmi: Avoid full hdmi audio fifo writes
Date: Mon, 13 Jun 2022 16:47:47 +0200	[thread overview]
Message-ID: <20220613144800.326124-21-maxime@cerno.tech> (raw)
In-Reply-To: <20220613144800.326124-1-maxime@cerno.tech>

From: Dom Cobley <popcornmix@gmail.com>

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@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 4b73b4fea7ec..53cc0b7b664c 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -1955,10 +1955,10 @@ 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 |
-- 
2.36.1

