linux-kernel - Re: [PATCH v1] ALSA: hda/tas2781: Prevent throwing away custom calibration addresses

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Message-ID: 
 <CAGwozwEmz00SDE5-xZ40q9OJa=yvQZMEha+JoAMrX2Tsd-hRrQ@mail.gmail.com>
Date: Thu, 8 Jan 2026 10:22:29 +0200
From: Antheas Kapenekakis <lkml@...heas.dev>
To: Matthew Schwartz <matthew.schwartz@...ux.dev>
Cc: Shenghao Ding <shenghao-ding@...com>, Baojun Xu <baojun.xu@...com>,
 tiwai@...e.de,
	linux-kernel@...r.kernel.org, linux-sound@...r.kernel.org
Subject: Re: [PATCH v1] ALSA: hda/tas2781: Prevent throwing away custom
 calibration addresses

On Thu, 8 Jan 2026 at 05:29, Matthew Schwartz
<matthew.schwartz@...ux.dev> wrote:
>
> On 1/7/26 2:21 AM, Antheas Kapenekakis wrote:
> > On Wed, 7 Jan 2026 at 12:17, Matthew Schwartz
> > <matthew.schwartz@...ux.dev> wrote:
> >>
> >>
> >>
> >>> On Jan 7, 2026, at 1:32 AM, Antheas Kapenekakis <lkml@...heas.dev> wrote:
> >>>
> >>> The V2 UEFI spec for per-device calibration data in TAS allows for
> >>> manufacturers to specify up to five custom calibration register
> >>> addresses and values to optimize per-device in factory.
> >>>
> >>> A basic description of the spec is found in a comment in function
> >>> tas2781_apply_calib(). However, currently, for the condition of
> >>> p->dspbin_typ != TASDEV_BASIC, if custom calibration addresses have been
> >>> provided by the manufacturer, they are ignored and the ones listed in
> >>> firmware are used.
> >>>
> >>> In case the manufacturer chose to change different registers other than
> >>> the default ones (r0, invr0, r0_low, pow, tlimit), this causes the
> >>> UEFI calibration data to scratch different registers and cause the
> >>> firmware to misbehave. This is true in the Xbox ROG Ally X, for one of
> >>> the firmwares, where it pops and has audio dropouts after the
> >>> calibration data is applied.
> >>>
> >>> Therefore, add a new bool to indicate that UEFI supplied custom
> >>> calibration addresses, and if so, use them regardless of dspbin_typ.
> >>>
> >>> Link: https://lore.kernel.org/all/CAGwozwFQKoQgo_Q=qdr-FTD+uoVWA8AtHyDmKwTOV4ZU6+F3SQ@mail.gmail.com/
> >>> Reported-by: Matthew Schwartz <matthew.schwartz@...ux.dev>
> >>> Closes: https://lore.kernel.org/all/0ba100d0-9b6f-4a3b-bffa-61abe1b46cd5@linux.dev/
> >>> Co-developed-by: Matthew Schwartz <matthew.schwartz@...ux.dev>
> >>> Signed-off-by: Matthew Schwartz <matthew.schwartz@...ux.dev>
> >>> Signed-off-by: Antheas Kapenekakis <lkml@...heas.dev>
> >>>
> >>> ---
> >>> @Matt: can you kindly verify this patch works for you?
> >>
> >> I’ll have time to debug it more in the morning but the patch does not work, it’s still using the same calibrated data as before with dropouts.
> >
> > If you can check that the register addresses changed that would be
> > great. Especially that we enter and exit the calibration block.
> > Perhaps that was happening before as well and the addresses were
> > overwritten by firmware later
>
> [    2.415699] snd_hda_codec_alc269 hdaudioC1D0: bound i2c-TXNW2781:00-tas2781-hda.0 (ops tas2781_hda_comp_ops [snd_hda_scodec_tas2781_i2c])
> [    2.417548] tas2781-hda i2c-TXNW2781:00-tas2781-hda.0: dspbin_type_check: ppcver=0x19500 -> dspbin_typ=2 (0=none,1=BASIC,2=ALPHA,3=BETA)
> [    3.809849] tas2781-hda i2c-TXNW2781:00-tas2781-hda.0: tas2781_apply_calib: enter, dspbin_typ=2, chip_id=0xadd
> [    3.809855] tas2781-hda i2c-TXNW2781:00-tas2781-hda.0: tas2781_apply_calib: default cali_reg: r0=0xbf4 invr0=0xc0c r0_low=0xc14 pow=0x9f0 tlimit=0xc7c
> [    3.809858] tas2781-hda i2c-TXNW2781:00-tas2781-hda.0: tas2781_apply_calib: UEFI custom cali_reg found: r0=0xce4 invr0=0xcf4 r0_low=0xcfc pow=0xae0 tlimit=0xd70
> [    3.809860] tas2781-hda i2c-TXNW2781:00-tas2781-hda.0: tas2781_apply_calib: using cali_reg for r->regs (custom_addr=1, dspbin_typ=2)
> [    3.809861] tas2781-hda i2c-TXNW2781:00-tas2781-hda.0: tas2781_apply_calib: exit, total_sz=42, is_user_space_calidata=1
> [    6.180351] tas2781-hda i2c-TXNW2781:00-tas2781-hda.0: tas2781_hda_playback_hook: action = 0
> [    6.330017] tas2781-hda i2c-TXNW2781:00-tas2781-hda.0: tasdev_load_calibrated_data: enter dev 0, is_user_space_calidata=1
> [    6.330021] tas2781-hda i2c-TXNW2781:00-tas2781-hda.0: tasdev_load_calibrated_data: writing UEFI cal data to regs: r0=0xce4 invr0=0xcf4 r0_low=0xcfc pow=0xae0 tlimit=0xd70
> [    6.330022] tas2781-hda i2c-TXNW2781:00-tas2781-hda.0: tasdev_load_calibrated_data: cal values: r0=3c5f7222 invr0=10f615d5
> [    6.332137] tas2781-hda i2c-TXNW2781:00-tas2781-hda.0: tasdev_load_calibrated_data: enter dev 1, is_user_space_calidata=1
> [    6.332138] tas2781-hda i2c-TXNW2781:00-tas2781-hda.0: tasdev_load_calibrated_data: writing UEFI cal data to regs: r0=0xce4 invr0=0xcf4 r0_low=0xcfc pow=0xae0 tlimit=0xd70
> [    6.332138] tas2781-hda i2c-TXNW2781:00-tas2781-hda.0: tasdev_load_calibrated_data: cal values: r0=3c90e72d invr0=10e83c28
>
> Looks like the addresses changed. I'm just going to send out a patch to skip calibration for the device as Jim suggested, as that is confirmed to work.

The addresses did not change

>From a previous email:
    r0_reg=0x000ce4 40cccccd
    r0_reg=0x000ce4 3c90e72d
 invr0_reg=0x000cf4 0fcd6e9e
 invr0_reg=0x000cf4 10e83c28
r0_low_reg=0x000cfc 0f8d4fdf
r0_low_reg=0x000cfc 2ec1c8ff
   pow_reg=0x000ae0 009b9c58
   pow_reg=0x000ae0 0096cefc
tlimit_reg=0x000d70 25800000
tlimit_reg=0x000d70 25800000

So the firmware data register overrides are correct and 0x80 addresses
can be ignored by the UEFI parser.

Well that's unfortunate. I'm not sure where to go from here

Antheas



> >
> > Antheas
> >
> >>>
> >>> Then verify your sign-off for the coby tag. If you would rather a
> >>> different acknowledgment tag (e.g., tested-by or suggested-by), lmk
> >>>
> >>> Thanks.
> >>> Antheas
> >>> ---
> >>> sound/hda/codecs/side-codecs/tas2781_hda.c | 4 +++-
> >>> 1 file changed, 3 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/sound/hda/codecs/side-codecs/tas2781_hda.c b/sound/hda/codecs/side-codecs/tas2781_hda.c
> >>> index 96e6d82dc69e..6efdf0a3442b 100644
> >>> --- a/sound/hda/codecs/side-codecs/tas2781_hda.c
> >>> +++ b/sound/hda/codecs/side-codecs/tas2781_hda.c
> >>> @@ -64,6 +64,7 @@ static void tas2781_apply_calib(struct tasdevice_priv *p)
> >>>       TASDEVICE_REG(0, 0x18, 0x7c),
> >>>   };
> >>>   unsigned int crc, oft, node_num;
> >>> +    bool custom_addr = false;
> >>>   unsigned char *buf;
> >>>   int i, j, k, l;
> >>>
> >>> @@ -104,6 +105,7 @@ static void tas2781_apply_calib(struct tasdevice_priv *p)
> >>>       for (j = 0, k = 0; j < node_num; j++) {
> >>>           oft = j * 6 + 3;
> >>>           if (tmp_val[oft] == TASDEV_UEFI_CALI_REG_ADDR_FLG) {
> >>> +                custom_addr = true;
> >>>               for (i = 0; i < TASDEV_CALIB_N; i++) {
> >>>                   buf = &data[(oft + i + 1) * 4];
> >>>                   cali_reg[i] = TASDEVICE_REG(buf[1],
> >>> @@ -151,7 +153,7 @@ static void tas2781_apply_calib(struct tasdevice_priv *p)
> >>>       }
> >>>   }
> >>>
> >>> -    if (p->dspbin_typ == TASDEV_BASIC) {
> >>> +    if (custom_addr || p->dspbin_typ == TASDEV_BASIC) {
> >>>       r->r0_reg = cali_reg[0];
> >>>       r->invr0_reg = cali_reg[1];
> >>>       r->r0_low_reg = cali_reg[2];
> >>>
> >>> base-commit: 9ace4753a5202b02191d54e9fdf7f9e3d02b85eb
> >>> --
> >>> 2.52.0
> >>
> >
>
>