Commit 59f8b2b7 authored by Dom Cobley's avatar Dom Cobley Committed by Dave Stevenson
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drm/vc4: hdmi: Increase audio MAI fifo dreq threshold 



Now we wait for write responses and have a burst
size of 4, we can set the fifo threshold much higher.

Set it to 28 (of the 32 entry size) to keep fifo
fuller and reduce chance of underflow.

Signed-off-by: default avatarDom Cobley <popcornmix@gmail.com>
Reviewed-by: default avatarMaxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240621152055.4180873-8-dave.stevenson@raspberrypi.com


Signed-off-by: default avatarDave Stevenson <dave.stevenson@raspberrypi.com>
parent 014eccc9

drivers/gpu/drm/vc4/vc4_hdmi.c

+13 −5
Original line number Diff line number Diff line
@@ -2047,6 +2047,7 @@ static int vc4_hdmi_audio_prepare(struct device *dev, void *data, 
	struct vc4_hdmi *vc4_hdmi = dev_get_drvdata(dev);

	struct drm_device *drm = vc4_hdmi->connector.dev;

	struct drm_connector *connector = &vc4_hdmi->connector;

	struct vc4_dev *vc4 = to_vc4_dev(drm);

	unsigned int sample_rate = params->sample_rate;

	unsigned int channels = params->channels;

	unsigned long flags;
@@ -2104,11 +2105,18 @@ static int vc4_hdmi_audio_prepare(struct device *dev, void *data, 
					     VC4_HDMI_AUDIO_PACKET_CEA_MASK);



	/* Set the MAI threshold */

	if (vc4->is_vc5)

		HDMI_WRITE(HDMI_MAI_THR,

		   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));

			   VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_PANICHIGH) |

			   VC4_SET_FIELD(0x10, VC4_HD_MAI_THR_PANICLOW) |

			   VC4_SET_FIELD(0x1c, VC4_HD_MAI_THR_DREQHIGH) |

			   VC4_SET_FIELD(0x1c, VC4_HD_MAI_THR_DREQLOW));

	else

		HDMI_WRITE(HDMI_MAI_THR,

			   VC4_SET_FIELD(0x8, VC4_HD_MAI_THR_PANICHIGH) |

			   VC4_SET_FIELD(0x8, VC4_HD_MAI_THR_PANICLOW) |

			   VC4_SET_FIELD(0x6, VC4_HD_MAI_THR_DREQHIGH) |

			   VC4_SET_FIELD(0x8, VC4_HD_MAI_THR_DREQLOW));



	HDMI_WRITE(HDMI_MAI_CONFIG,

		   VC4_HDMI_MAI_CONFIG_BIT_REVERSE |