Add dp sound by NekoCWD · Pull Request #443 · AsahiLinux/linux

NekoCWD · 2026-01-26T23:08:29Z

This enables audio via DP alt mode on t8103 based devices

Tested on macbook air m1 (j313) with LG tv

TV EDID

Decoded EDID

> edid-decode /sys/class/drm/card1-DP-1/edid
edid-decode (hex):

00 ff ff ff ff ff ff 00 1e 6d 01 00 01 01 01 01
01 1b 01 03 80 a0 5a 78 0a ee 91 a3 54 4c 99 26
0f 50 54 a1 08 00 31 40 45 40 61 40 71 40 01 01
01 01 01 01 01 01 66 21 50 b0 51 00 1b 30 40 70
36 00 40 84 63 00 00 1e 64 19 00 40 41 00 26 30
18 88 36 00 40 84 63 00 00 18 00 00 00 fd 00 3a
3e 1e 53 10 00 0a 20 20 20 20 20 20 00 00 00 fc
00 4c 47 20 54 56 0a 20 20 20 20 20 20 20 01 72

02 03 25 f1 4e 10 1f 04 93 05 14 03 02 12 20 21
22 15 01 29 15 07 50 09 07 07 55 07 00 67 03 0c
00 20 00 80 1e 01 1d 80 18 71 1c 16 20 58 2c 25
00 a0 5a 00 00 00 9e 01 1d 00 72 51 d0 1e 20 6e
28 55 00 20 c2 31 00 00 1e 8c 0a d0 8a 20 e0 2d
10 10 3e 96 00 a0 5a 00 00 00 18 02 3a 80 18 71
38 2d 40 58 2c 45 00 a0 5a 00 00 00 1e 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 39

----------------

Block 0, Base EDID:
EDID Structure Version & Revision: 1.3
Vendor & Product Identification:
  Manufacturer: GSM
  Model: 1
  Serial Number: 16843009 (0x01010101)
  Made in: week 1 of 2017
Basic Display Parameters & Features:
  Digital display
  Maximum image size: 160 cm x 90 cm
  Gamma: 2.20
  RGB color display
  First detailed timing is the preferred timing
Color Characteristics:
  Red  : 0.6396, 0.3300
  Green: 0.2998, 0.5996
  Blue : 0.1503, 0.0595
  White: 0.3125, 0.3291
Established Timings I & II:
  IBM     :   720x400    70.081663 Hz   9:5     31.467 kHz     28.320000 MHz
  DMT 0x04:   640x480    59.940476 Hz   4:3     31.469 kHz     25.175000 MHz
  DMT 0x09:   800x600    60.316541 Hz   4:3     37.879 kHz     40.000000 MHz
  DMT 0x10:  1024x768    60.003840 Hz   4:3     48.363 kHz     65.000000 MHz
Standard Timings:
  DMT 0x04:   640x480    59.940476 Hz   4:3     31.469 kHz     25.175000 MHz
  DMT 0x09:   800x600    60.316541 Hz   4:3     37.879 kHz     40.000000 MHz
  DMT 0x10:  1024x768    60.003840 Hz   4:3     48.363 kHz     65.000000 MHz
  GTF     :  1152x864    60.000000 Hz   4:3     53.700 kHz     81.624000 MHz
Detailed Timing Descriptors:
  DTD 1:  1360x768    60.015162 Hz  85:48    47.712 kHz     85.500000 MHz (1600 mm x 900 mm)
               Hfront   64 Hsync 112 Hback  256 Hpol P
               Vfront    3 Vsync   6 Vback   18 Vpol P
  DTD 2:  1024x768    60.003840 Hz   4:3     48.363 kHz     65.000000 MHz (1600 mm x 900 mm)
               Hfront   24 Hsync 136 Hback  160 Hpol N
               Vfront    3 Vsync   6 Vback   29 Vpol N
  Display Range Limits:
    Monitor ranges (GTF): 58-62 Hz V, 30-83 kHz H, max dotclock 160 MHz
  Display Product Name: 'LG TV'
Extension blocks: 1
Checksum: 0x72

----------------

Block 1, CTA-861 Extension Block:
Revision: 3
Underscans IT Video Formats by default
Basic audio support
Supports YCbCr 4:4:4
Supports YCbCr 4:2:2
Native detailed modes: 1
Video Data Block:
  VIC  16:  1920x1080   60.000000 Hz  16:9     67.500 kHz    148.500000 MHz
  VIC  31:  1920x1080   50.000000 Hz  16:9     56.250 kHz    148.500000 MHz
  VIC   4:  1280x720    60.000000 Hz  16:9     45.000 kHz     74.250000 MHz
  VIC  19:  1280x720    50.000000 Hz  16:9     37.500 kHz     74.250000 MHz (native)
  VIC   5:  1920x1080i  60.000000 Hz  16:9     33.750 kHz     74.250000 MHz
  VIC  20:  1920x1080i  50.000000 Hz  16:9     28.125 kHz     74.250000 MHz
  VIC   3:   720x480    59.940060 Hz  16:9     31.469 kHz     27.000000 MHz
  VIC   2:   720x480    59.940060 Hz   4:3     31.469 kHz     27.000000 MHz
  VIC  18:   720x576    50.000000 Hz  16:9     31.250 kHz     27.000000 MHz
  VIC  32:  1920x1080   24.000000 Hz  16:9     27.000 kHz     74.250000 MHz
  VIC  33:  1920x1080   25.000000 Hz  16:9     28.125 kHz     74.250000 MHz
  VIC  34:  1920x1080   30.000000 Hz  16:9     33.750 kHz     74.250000 MHz
  VIC  21:  1440x576i   50.000000 Hz   4:3     15.625 kHz     27.000000 MHz
  VIC   1:   640x480    59.940476 Hz   4:3     31.469 kHz     25.175000 MHz
Audio Data Block:
  AC-3:
    Max channels: 6
    Supported sample rates (kHz): 48 44.1 32
    Maximum bit rate: 640 kb/s
  Linear PCM:
    Max channels: 2
    Supported sample rates (kHz): 48 44.1 32
    Supported sample sizes (bits): 24 20 16
  Enhanced AC-3 (DD+):
    Max channels: 6
    Supported sample rates (kHz): 48 44.1 32
Vendor-Specific Data Block (HDMI), OUI 00-0C-03:
  Source physical address: 2.0.0.0
  Supports_AI
  Maximum TMDS clock: 150 MHz
Detailed Timing Descriptors:
  DTD 3:  1920x1080i  60.000000 Hz  16:9     33.750 kHz     74.250000 MHz (160 mm x 90 mm)
               Hfront   88 Hsync  44 Hback  148 Hpol P
               Vfront    2 Vsync   5 Vback   15 Vpol P Vfront +0.5 Odd Field
               Vfront    2 Vsync   5 Vback   15 Vpol P Vback  +0.5 Even Field
  DTD 4:  1280x720    60.000000 Hz  16:9     45.000 kHz     74.250000 MHz (800 mm x 450 mm)
               Hfront  110 Hsync  40 Hback  220 Hpol P
               Vfront    5 Vsync   5 Vback   20 Vpol P
  DTD 5:   720x480    59.940060 Hz   3:2     31.469 kHz     27.000000 MHz (160 mm x 90 mm)
               Hfront   16 Hsync  62 Hback   60 Hpol N
               Vfront    9 Vsync   6 Vback   30 Vpol N
  DTD 6:  1920x1080   60.000000 Hz  16:9     67.500 kHz    148.500000 MHz (160 mm x 90 mm)
               Hfront   88 Hsync  44 Hback  148 Hpol P
               Vfront    4 Vsync   5 Vback   36 Vpol P
Checksum: 0x39  Unused space in Extension Block: 18 bytes

HDMI audio woks unpredictable, but there are some general tips:

Stop pipewire before connecting display
Restart pipewire if you don't see audio device

Some things to test (can improve stability):

Implicitly set format in wireplumber config - Stability improved, but no-sound issue still here
Play with alsa.* settings in wireplumber config
Disabled suspend allows us to keep audio playing after pause
Dig into format/rate/chmap selection in driver

Tracker: #364

HDP status for DisplayPort alt-mode is signaled data_status. Track changes to have a debounced HPD to forward to the DRM KMS driver. Signed-off-by: Janne Grunau <j@jannau.net>

This is not how dp-altmode support should be implemented but it works for new. Requires a "displayport" property in the connector node with a phandle of the connector. Signed-off-by: Janne Grunau <j@jannau.net>

Enable DP alt mode for all M1 devices: - Mac Mini (M1): USB-C port next to the HDMI port - Macbook Pro (M1, 13-inch): front left USB-C port - Macbook Air (M1, 13-inch): front left USB-C port - iMac (M1, 2 USB-C ports): back left USB-C port - iMac (M1, 4 USB-C ports): back right middle USB-C port Signed-off-by: Janne Grunau <j@jannau.net>

Works around missing suspend/resume handling in ATC phy for DP-altmode. Signed-off-by: Janne Grunau <j@jannau.net>

Enable DP alt mode for the front left USB-C port of Macbook Air 13 (M2, 13/15-inch) and Macbook Pro (M2, 13-inch). Can't easily enabled on on the M2 Mac Mini since dcpext is used for the HDMI port and dcp bringup is troublesome. Signed-off-by: Janne Grunau <j@jannau.net>

Works around missing suspend/resume handling in ATC phy for DP-altmode. Signed-off-by: Janne Grunau <j@jannau.net>

Needs more testing, maybe a little unstable and somehow limits the HDMI out to 1280x720 (to be verified). Using dcp as display coproc since dcpext is used for the HDMI port. Signed-off-by: Janne Grunau <j@jannau.net>

Works around missing suspend/resume handling in ATC phy for DP-altmode. Signed-off-by: Janne Grunau <j@jannau.net>

Blessed dp-altmode port is front left port on j314/j316/j414/j416. Signed-off-by: Janne Grunau <j@jannau.net>

…ways on Works around missing suspend/resume handling in ATC phy for DP-altmode. Signed-off-by: Janne Grunau <j@jannau.net>

DP alt mode for Mac Studio, the blessed port is the back left middle port (second closest USB-C port to the power connector). Signed-off-by: Janne Grunau <j@jannau.net>

…s on Works around missing suspend/resume handling in ATC phy for DP-altmode. Signed-off-by: Janne Grunau <j@jannau.net>

DP alt mode for Mac Mini M2 Pro, the blessed port is the back right middle port (second closest USB-C port to the power connector). Signed-off-by: Janne Grunau <j@jannau.net>

This enables setting up sio node. &sio required by apple dcp audio Signed-off-by: Vasiliy Doylov <nekocwd@mainlining.org>

NekoCWD · 2026-01-27T08:30:36Z

Some testing on format hardcode:

monitor.alsa.rules = [
  {
    matches = [
      {
        # Matches all sinks
        node.name = "~alsa_output.platform-238334000.audio-controller.*"
      }
    ]
    actions = {
      update-props = {
        audio.format           = "S16LE"
        audio.rate             = 48000
        api.alsa.period-size   = 4096
        api.alsa.period-num    = 6
        api.alsa.headroom      = 512
        session.suspend-timeout-seconds = 0
     }
    }
  }
]

This wireplumber config results in stable sound on 1/5 pipewire restarts

jannau added 30 commits January 24, 2026 19:47

Merge branch 'bits/000-devicetree' into asahi-wip

bc5f26e

Merge branch 'bits/002-backports' into asahi-wip

0f1e25c

Merge branch 'bits/010-soc' into asahi-wip

86a435f

Merge branch 'bits/020-dart' into asahi-wip

540540d

Merge branch 'bits/030-misc' into asahi-wip

b2f2747

Merge branch 'bits/040-dwc3' into asahi-wip

72ba8e7

Merge branch 'bits/050-nvme' into asahi-wip

18792a3

Merge branch 'bits/070-audio' into asahi-wip

7b79964

Merge branch 'bits/080-wifi' into asahi-wip

066214a

Merge branch 'bits/090-spi-hid' into asahi-wip

21d842f

Merge branch 'bits/110-smc' into asahi-wip

7b5d694

Merge branch 'bits/140-pci' into asahi-wip

f34e9f9

Merge branch 'bits/150-xhci-firmware' into asahi-wip

8bc119a

Merge branch 'bits/170-atcphy' into asahi-wip

221e6e9

Merge branch 'bits/180-sio' into asahi-wip

e87d9a4

Merge branch 'bits/190-rust' into asahi-wip

1976bc2

Merge branch 'bits/200-dcp' into asahi-wip

a2d51ee

Merge branch 'bits/210-gpu' into asahi-wip

d99ac96

Merge branch 'bits/220-tso' into asahi-wip

8c83886

Merge branch 'bits/240-isp' into asahi-wip

aa304cc

Merge branch 'bits/250-aop' into asahi-wip

3725b04

usb: typec: tipd: Track data_status changes for CD321x

44289ee

HDP status for DisplayPort alt-mode is signaled data_status. Track changes to have a debounced HPD to forward to the DRM KMS driver. Signed-off-by: Janne Grunau <j@jannau.net>

usb: typec: tipd: HACK: Use drm oob hotplug event

02113c7

This is not how dp-altmode support should be implemented but it works for new. Requires a "displayport" property in the connector node with a phandle of the connector. Signed-off-by: Janne Grunau <j@jannau.net>

HACK: arm64: dts: apple: t8103: Mark ps_atc1_common as always on

383d3b6

Works around missing suspend/resume handling in ATC phy for DP-altmode. Signed-off-by: Janne Grunau <j@jannau.net>

HACK: arm64: dts: apple: t8112: Mark ps_atc1_common as always on

e84d797

Works around missing suspend/resume handling in ATC phy for DP-altmode. Signed-off-by: Janne Grunau <j@jannau.net>

arm64: apple: t8112-j473: Add DP-altmode on typec1

9a5c74c

Needs more testing, maybe a little unstable and somehow limits the HDMI out to 1280x720 (to be verified). Using dcp as display coproc since dcpext is used for the HDMI port. Signed-off-by: Janne Grunau <j@jannau.net>

HACK: arm64: apple: t8112-j473: Mark ps_atc1_common as always on

2cffbac

Works around missing suspend/resume handling in ATC phy for DP-altmode. Signed-off-by: Janne Grunau <j@jannau.net>

arm64: dts: apple: t60xx: j[34]1[46]: Add dp-altmode hacks

8fd2eba

Blessed dp-altmode port is front left port on j314/j316/j414/j416. Signed-off-by: Janne Grunau <j@jannau.net>

jannau and others added 5 commits January 26, 2026 19:39

HACK: arm64: dts: apple: t60xx: j[34]1[46]: Mark ps_atc1_common as al…

a8848a7

…ways on Works around missing suspend/resume handling in ATC phy for DP-altmode. Signed-off-by: Janne Grunau <j@jannau.net>

arm64: dts: apple: t60xx: j[34]75: Add dp-altmode hacks

68feab3

DP alt mode for Mac Studio, the blessed port is the back left middle port (second closest USB-C port to the power connector). Signed-off-by: Janne Grunau <j@jannau.net>

HACK: arm64: dts: apple: t60xx: j[34]75: Mark ps_atc1_common as alway…

ecc5cfa

…s on Works around missing suspend/resume handling in ATC phy for DP-altmode. Signed-off-by: Janne Grunau <j@jannau.net>

arm64: dts: apple: t6020-j474s: Add dp-altmode hacks

b0b5bbf

DP alt mode for Mac Mini M2 Pro, the blessed port is the back right middle port (second closest USB-C port to the power connector). Signed-off-by: Janne Grunau <j@jannau.net>

arm64: dts: apple: t8103: add &sio alias so m1n1 can handle it correctly

8b69f33

This enables setting up sio node. &sio required by apple dcp audio Signed-off-by: Vasiliy Doylov <nekocwd@mainlining.org>

reviczky mentioned this pull request Jan 27, 2026

DisplayPort / Thunderbolt / USB4 reviczky/asahi#21

Open

jannau force-pushed the fairydust branch from b0b5bbf to 61b6e71 Compare February 15, 2026 15:05

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Add dp sound#443

Add dp sound#443
NekoCWD wants to merge 35 commits intoAsahiLinux:fairydustfrom
NekoCWD:asahi-fairydust/dp-sound

NekoCWD commented Jan 26, 2026 •

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NekoCWD commented Jan 27, 2026 •

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NekoCWD commented Jan 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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This enables audio via DP alt mode on t8103 based devices

HDMI audio woks unpredictable, but there are some general tips:

Some things to test (can improve stability):

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NekoCWD commented Jan 27, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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NekoCWD commented Jan 26, 2026 •

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NekoCWD commented Jan 27, 2026 •

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