CS35L41 amplifiers in an ASUS Zenbook on linux

cs35l41_spi.md

Asus Zenbook UX3402 speakers on Linux

I got the speakers working on my Asus Zenbook 14 OLED UX3402, the one with Intel CPU and the two CS35L41 audio amplifiers connected over SPI (not the UM3402YA, with AMD and I²C). The amplifiers are supported by the snd_hda_scodec_cs35l41 module in recent kernel versions, but they require some model-specific configuration paramaters, that should be provided by the BIOS, via ACPI. Of course, they are missing. It seems that the Windows drivers have those parameters somehow hardcoded, instead of using ACPI (bad idea, but who am I to criticise). Since Asus has been nasty and refused/was not able to update the BIOS with the missing data, I have patched the ACPI tables myself.

Warning
As stated by Cirrus developers, if you try this there is a non-zero (low, I hope) possibility of blowing your speakers. Take into account that this procedure is not just configuring your box, it is hardware-level hacking with very scarce information about the hardware (thank you, ASUS, and thank you, Cirrus, for not publishing the CS35L41 datasheet and making it only available by request). Additionally, You should know how to work with DSDT files (I have a brief guide here) and how to recover from a non booting system. You are on your own. You have been warned.

My BIOS is the most recent one (version 310). I have added two _DSD objects in the disassembled DSDT file (dsdt.dsl):

• One inside the SPK1 device, providing the missing "cirrus,dev-index" and other properties, just like the I2C models. You can also provide these properties by patching the kernel module (the linux/sound/pci/hda/cs35l41_hda.c file).

• Another one, after the SPK1 device, with the chip select GPIOs, "cs-gpios", required by the SPI bus (the somehow simpler I²C bus does not use chip select pins, but addresses). Without this _DSD object, only one amplifier can be addressed and activated. In this case, the driver refuses to load even for this single working amplifier.

Obsolete

I keep the old, original patch, that produced AMP short error messages when the volume was high enough, for reference. Please try first the simpler patch with external boost, that seems to work without flaws (thanks to @bdandy, see the comment).

Boot log

Output from journalctl -b -g CSC3551 --output short-monotonic after the old patch:

[5.358062] zenbook kernel: Serial bus multi instantiate pseudo device driver CSC3551:00: Instantiated 2 SPI devices.
[5.643640] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: Cirrus Logic CS35L41 (35a40), Revision: B2
[5.680302] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: Cirrus Logic CS35L41 (35a40), Revision: B2
[5.996217] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: Falling back to default firmware.
[5.996608] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: DSP1: Firmware version: 3
[5.996611] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: DSP1: cirrus/cs35l41-dsp1-spk-prot.wmfw: Fri 24 Jun 2022 14:55:56 GMT Daylight Time
[6.069598] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: DSP1: Firmware: 400a4 vendor: 0x2 v0.58.0, 2 algorithms
[6.070173] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: DSP1: 0: ID cd v29.78.0 XM@94 YM@e
[6.070185] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: DSP1: 1: ID f20b v0.1.0 XM@17c YM@0
[6.070192] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: DSP1: spk-prot: e:\workspace\workspace\tibranch_release_playback_6.76_2\ormis\staging\default_tunings\internal\CS35L53\Fixed_Attenuation_Mono_48000_29.78.0\full\Fixed_Attenuation_Mono_48000_29.78.0_full.bin
[6.083485] zenbook kernel: snd_hda_codec_realtek ehdaudio0D0: bound spi1-CSC3551:00-cs35l41-hda.0 (ops cs35l41_hda_comp_ops [snd_hda_scodec_cs35l41])
[6.083899] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: Falling back to default firmware.
[6.083962] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: DSP1: Firmware version: 3
[6.083966] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: DSP1: cirrus/cs35l41-dsp1-spk-prot.wmfw: Fri 24 Jun 2022 14:55:56 GMT Daylight Time
[6.145224] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: DSP1: Firmware: 400a4 vendor: 0x2 v0.58.0, 2 algorithms
[6.145817] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: DSP1: 0: ID cd v29.78.0 XM@94 YM@e
[6.145828] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: DSP1: 1: ID f20b v0.1.0 XM@17c YM@0
[6.145834] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: DSP1: spk-prot: e:\workspace\workspace\tibranch_release_playback_6.76_2\ormis\staging\default_tunings\internal\CS35L53\Fixed_Attenuation_Mono_48000_29.78.0\full\Fixed_Attenuation_Mono_48000_29.78.0_full.bin
[6.161484] zenbook kernel: snd_hda_codec_realtek ehdaudio0D0: bound spi1-CSC3551:00-cs35l41-hda.1 (ops cs35l41_hda_comp_ops [snd_hda_scodec_cs35l41])

The "Falling back to default firmware" disappears if spk-id-gpios are provided (the block is commented in the patch). As a result, a different firmware is loaded, resulting in very low volume and strong distortion. If the new patch is used, that uses external boost, the sound is correct, and the log is

[4.534361] zenbook kernel: Serial bus multi instantiate pseudo device driver CSC3551:00: Instantiated 2 SPI devices.
[4.857006] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: Cirrus Logic CS35L41 (35a40), Revision: B2
[4.865816] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: Reset line busy, assuming shared reset
[4.892724] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: Cirrus Logic CS35L41 (35a40), Revision: B2
[5.104155] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: DSP1: Firmware version: 3
[5.104161] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: DSP1: cirrus/cs35l41-dsp1-spk-prot-10431e02.wmfw: Fri 27 Aug 2021 14:58:19 W. Europe Daylight Time
[5.177897] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: DSP1: Firmware: 400a4 vendor: 0x2 v0.43.1, 2 algorithms
[5.178547] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: DSP1: 0: ID cd v29.63.1 XM@94 YM@e
[5.178561] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: DSP1: 1: ID f20b v0.1.0 XM@176 YM@0
[5.178569] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.0: DSP1: spk-prot: C:\Users\tyang\Desktop\Product Setting\SmartAMP\ASUS\ASUS_Zenbook\UX3402\Tuning Release\220304\ASUS_UX3402_L_tuning_IDYC_ReDc_PICL_RTL_0304.bin
[5.204190] zenbook kernel: snd_hda_codec_realtek ehdaudio0D0: bound spi1-CSC3551:00-cs35l41-hda.0 (ops cs35l41_hda_comp_ops [snd_hda_scodec_cs35l41])
[5.204529] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: DSP1: Firmware version: 3
[5.204534] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: DSP1: cirrus/cs35l41-dsp1-spk-prot-10431e02.wmfw: Fri 27 Aug 2021 14:58:19 W. Europe Daylight Time
[5.266164] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: DSP1: Firmware: 400a4 vendor: 0x2 v0.43.1, 2 algorithms
[5.266764] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: DSP1: 0: ID cd v29.63.1 XM@94 YM@e
[5.266776] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: DSP1: 1: ID f20b v0.1.0 XM@176 YM@0
[5.266784] zenbook kernel: cs35l41-hda spi1-CSC3551:00-cs35l41-hda.1: DSP1: spk-prot: C:\Users\tyang\Desktop\Product Setting\SmartAMP\ASUS\ASUS_Zenbook\UX3402\Tuning Release\220304\ASUS_UX3402_R_tuning_IDYC_ReDc_PICL_RTL_0304.bin
[5.293339] zenbook kernel: snd_hda_codec_realtek ehdaudio0D0: bound spi1-CSC3551:00-cs35l41-hda.1 (ops cs35l41_hda_comp_ops [snd_hda_scodec_cs35l41])

dsdt.dsl-old.patch

--- dsdt.dsl.old	2023-03-26 01:06:48.845795666 +0100
+++ dsdt.dsl	2023-03-26 12:00:45.643851841 +0200
@@ -18,7 +18,7 @@
  *     Compiler ID      "INTL"
  *     Compiler Version 0x20200717 (538969879)
  */
-DefinitionBlock ("", "DSDT", 2, "_ASUS_", "Notebook", 0x01072009)
+DefinitionBlock ("", "DSDT", 2, "_ASUS_", "Notebook", 0x0107200A)
 {
     /*
      * iASL Warning: There were 233 external control methods found during
@@ -90642,7 +90642,48 @@
             Method (_DIS, 0, NotSerialized)  // _DIS: Disable Device
             {
             }
+
+            Name (_DSD, Package ()   // _DSD: Device-Specific Data
+            {
+                ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), 
+                Package ()
+                {
+                    Package () { "cirrus,dev-index", Package () { Zero, One }},
+                    Package () { "reset-gpios", Package () {
+                       SPK1, One, Zero, Zero,
+                       SPK1, One, Zero, Zero,
+                    } },
+                    // Package () { "spk-id-gpios", Package () {
+                    //    SPK1, 0x02, Zero, Zero,
+                    //    SPK1, 0x02, Zero, Zero,
+                    // } },
+                    Package () { "cirrus,speaker-position",     Package () { Zero, One } },
+                    Package () { "cirrus,gpio1-func",           Package () { Zero, Zero } },
+                    Package () { "cirrus,gpio2-func",           Package () { 0x02, 0x02 } },
+                    // boost-type: 0 internal, 1 external
+                    Package () { "cirrus,boost-type",           Package () { Zero, Zero } },
+                    // boost-peak-milliamp: 1600 to 4500, increments of 50 mA
+                    Package () { "cirrus,boost-peak-milliamp",  Package () { 4500, 4500 } },
+                    // boost-ind-nanohenry: 1000 | 1200 | 1500 | 2200 nH
+                    Package () { "cirrus,boost-ind-nanohenry",  Package () { 1000, 1000 } },
+                    // boost-cap-microfarad: rounded to the nearest integer
+                    Package () { "cirrus,boost-cap-microfarad", Package () { 24, 24 } },
+                },
+            })
         }
+
+        Name (_DSD, Package ()
+        {
+            ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), 
+            Package ()
+            {
+                Package () { "cs-gpios", Package () { 
+                    Zero,                    // Native CS
+                    SPK1, Zero, Zero, Zero   // GPIO CS
+                } }
+            }
+        })
+
     }
 
     Scope (_SB.PC00.LPCB)

dsdt.dsl.patch

--- dsdt.dsl.old	2023-03-26 01:06:48.845795666 +0100
+++ dsdt.dsl	2023-03-26 12:00:45.643851841 +0200
@@ -18,7 +18,7 @@
  *     Compiler ID      "INTL"
  *     Compiler Version 0x20200717 (538969879)
  */
-DefinitionBlock ("", "DSDT", 2, "_ASUS_", "Notebook", 0x01072009)
+DefinitionBlock ("", "DSDT", 2, "_ASUS_", "Notebook", 0x0107200A)
 {
     /*
      * iASL Warning: There were 233 external control methods found during
@@ -90642,7 +90642,43 @@
             Method (_DIS, 0, NotSerialized)  // _DIS: Disable Device
             {
             }
+
+            Name (_DSD, Package ()   // _DSD: Device-Specific Data
+            {
+                ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), 
+                Package ()
+                {
+                    Package () { "cirrus,dev-index", Package () { Zero, One }},
+                    Package () { "reset-gpios", Package () {
+                       SPK1, One, Zero, Zero,
+                       SPK1, One, Zero, Zero,
+                    } },
+                    Package () { "spk-id-gpios", Package () {
+                       SPK1, 0x02, Zero, Zero,
+                       SPK1, 0x02, Zero, Zero,
+                    } },
+                    Package () { "cirrus,speaker-position",     Package () { Zero, One } },
+                    // gpioX-func: 0 not used, 1 VPSK_SWITCH, 2: INTERRUPT, 3: SYNC
+                    Package () { "cirrus,gpio1-func",           Package () { One, One } },
+                    Package () { "cirrus,gpio2-func",           Package () { 0x02, 0x02 } },
+                    // boost-type: 0 internal, 1 external
+                    Package () { "cirrus,boost-type",           Package () { Zero, Zero } },
+                },
+            })
         }
+
+        Name (_DSD, Package ()
+        {
+            ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), 
+            Package ()
+            {
+                Package () { "cs-gpios", Package () { 
+                    Zero,                    // Native CS
+                    SPK1, Zero, Zero, Zero   // GPIO CS
+                } }
+            }
+        })
+
     }
 
     Scope (_SB.PC00.LPCB)