2020-03-30 07:32:17

by Tom Hebb

Subject: [PATCH 0/3] Properly fix headphone noise on the XPS 13 and other ALC256 devices

The root cause of various pervasive audio problems on the XPS 13
9350/9360, mostly relating to the headphone jack, turns out to be an
undocumented feature of the ALC256 and similar codecs that routes audio
along paths not exposed in the HDA node graph. The best we've had so far
to configure this feature is magic numbers provided by Realtek, none of
which have fully fixed all issues.

This series documents the "PC Beep Hidden Register", which controls the
feature and which I've reverse engineered using black box techniques,
and uses my findings to hopefully fix the headphone issues on my XPS 13
once and for all.


Thomas Hebb (3):
ALSA: doc: Document PC Beep Hidden Register on Realtek ALC256
ALSA: hda/realtek - Set principled PC Beep configuration for ALC256
ALSA: hda/realtek - Remove now-unnecessary XPS 13 headphone noise
fixups

Documentation/sound/hd-audio/index.rst | 1 +
Documentation/sound/hd-audio/models.rst | 2 -
.../sound/hd-audio/realtek-pc-beep.rst | 129 ++++++++++++++++++
sound/pci/hda/patch_realtek.c | 49 ++-----
4 files changed, 139 insertions(+), 42 deletions(-)
create mode 100644 Documentation/sound/hd-audio/realtek-pc-beep.rst

--
2.25.2

2020-03-30 08:04:25

by Takashi Iwai

Subject: Re: [PATCH 0/3] Properly fix headphone noise on the XPS 13 and other ALC256 devices

On Mon, 30 Mar 2020 09:30:29 +0200,
Thomas Hebb wrote:
>
>
> The root cause of various pervasive audio problems on the XPS 13
> 9350/9360, mostly relating to the headphone jack, turns out to be an
> undocumented feature of the ALC256 and similar codecs that routes audio
> along paths not exposed in the HDA node graph. The best we've had so far
> to configure this feature is magic numbers provided by Realtek, none of
> which have fully fixed all issues.
>
> This series documents the "PC Beep Hidden Register", which controls the
> feature and which I've reverse engineered using black box techniques,
> and uses my findings to hopefully fix the headphone issues on my XPS 13
> once and for all.

Thanks for the patches, all those look interesting and good to apply.
But I'd like to get it reviewed by Kailang at first -- in case we
might be playing with something untouchable.

Kailang, could you review this quickly?


Takashi

>
> Thomas Hebb (3):
> ALSA: doc: Document PC Beep Hidden Register on Realtek ALC256
> ALSA: hda/realtek - Set principled PC Beep configuration for ALC256
> ALSA: hda/realtek - Remove now-unnecessary XPS 13 headphone noise
> fixups
>
> Documentation/sound/hd-audio/index.rst | 1 +
> Documentation/sound/hd-audio/models.rst | 2 -
> .../sound/hd-audio/realtek-pc-beep.rst | 129 ++++++++++++++++++
> sound/pci/hda/patch_realtek.c | 49 ++-----
> 4 files changed, 139 insertions(+), 42 deletions(-)
> create mode 100644 Documentation/sound/hd-audio/realtek-pc-beep.rst
>
> --
> 2.25.2
>