ACK/Cmnt: [SRU] [L/Unstable] [PATCH 00/16] NULL pointer dereference on CS35L41 HDA AMP Edit

[Stefan Bader]

On 01.08.23 10:36, Kai-Heng Feng wrote:
> BugLink: https://bugs.launchpad.net/bugs/2029199
> 
> [Impact]
> NULL pointer dereference happens because the HDA driver is trying to use
> CS35L41 HDA AMP before its probe routine is fully realized.
> 
> [Fix]
> Use device link to enforce proper probe order.
> Since the fixing commit is part of a patch series, pull in the entire
> series which has several other important fixes too.
> 
> [Test]
> Use dmesg to see if there's error. With the fix applied, no more kernel
> splat can be found. Hence the system can perform suspend, reboot and
> shutdown normally.
> 
> [Where problems could occur]
> Though the entire series isn't trivia, it's not a major overhaul either.
> The entire changeset is limited to CS35L41 AMP, so the scope of
> regression risk is constrained.
> One possible risk factor is that it may require newer DSP firmware, and
> we'll monitor it closely on such scenario.
> 
> Lucas Tanure (3):
>    ASoC: cs35l41: Refactor error release code
>    ALSA: cs35l41: Add shared boost feature
>    ASoC: dt-bindings: cirrus,cs35l41: Document CS35l41 shared boost
> 
> Stefan Binding (13):
>    ALSA: hda: cs35l41: Ensure firmware/tuning pairs are always loaded
>    ALSA: hda: cs35l41: Enable Amp High Pass Filter
>    ALSA: cs35l41: Use mbox command to enable speaker output for external
>      boost
>    ALSA: cs35l41: Poll for Power Up/Down rather than waiting a fixed
>      delay
>    ALSA: hda: cs35l41: Check mailbox status of pause command after
>      firmware load
>    ALSA: hda: cs35l41: Ensure we correctly re-sync regmap before system
>      suspending.
>    ALSA: hda: cs35l41: Ensure we pass up any errors during system
>      suspend.
>    ALSA: hda: cs35l41: Move Play and Pause into separate functions
>    ALSA: hda: hda_component: Add pre and post playback hooks to
>      hda_component
>    ALSA: hda: cs35l41: Use pre and post playback hooks
>    ALSA: hda: cs35l41: Rework System Suspend to ensure correct call
>      separation
>    ALSA: hda: cs35l41: Add device_link between HDA and cs35l41_hda
>    ALSA: hda: cs35l41: Ensure amp is only unmuted during playback
> 
>   .../bindings/sound/cirrus,cs35l41.yaml        |  10 +-
>   include/sound/cs35l41.h                       |  14 +-
>   sound/pci/hda/cs35l41_hda.c                   | 395 ++++++++++++------
>   sound/pci/hda/hda_component.h                 |   2 +
>   sound/pci/hda/patch_realtek.c                 |  10 +-
>   sound/soc/codecs/cs35l41-lib.c                | 185 +++++++-
>   sound/soc/codecs/cs35l41.c                    | 101 ++---
>   sound/soc/codecs/cs35l41.h                    |   1 +
>   8 files changed, 522 insertions(+), 196 deletions(-)
> 
Alright, with the additional explanation I guess that risk is vaguely 
acceptable. Just please try to keep those bigger backports to a minimum.

Acked-by: Stefan Bader <stefan.bader at canonical.com>
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