Unverified Commit 8434111c authored by Dom Cobley's avatar Dom Cobley Committed by Maxime Ripard
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drm/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: default avatarDom Cobley <popcornmix@gmail.com>
Signed-off-by: default avatarMaxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20210525132354.297468-10-maxime@cerno.tech
parent 9a8fd277

drivers/gpu/drm/vc4/vc4_hdmi.c

+6 −16
Original line number Diff line number Diff line
@@ -1380,22 +1380,12 @@ static int vc4_hdmi_audio_hw_params(struct snd_pcm_substream *substream, 
	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 {

	/* 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 |