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

[Andrea Righi]

On Fri, Sep 01, 2023 at 12:18:07PM +0200, Stefan Bader wrote:
> 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(-)
> > 
> 
> This seems to be still missing from Mantic (I only attempted to find the
> commit title of patch 16/16).

They seem to be all upstream now, but they didn't land in v6.5. We will
apply all these fixes after we get a 6.5 kernel in release.

-Andrea