Re: NULL ptr dereference in cs42l43/cs35l56 on Lenovo Yoga 7 Slim laptop

[Charles Keepax <ckeepax@opensource.cirrus.com>]

On Wed, Nov 11, 2026 at 10:20:03AM +0000, Charles Keepax wrote:
> On Tue, Nov 10, 2026 at 01:30:52PM +0100, Krzysztof Hałasa wrote:
> > I'm trying to use some audio on a certain new laptop:
> > DMI: LENOVO 83R0/LNVNB161216, BIOS UCCN16WW 08/07/2026. Aka Yoga 7 Slim
> > 14ILL11 or something like that. Also LENOVO_MT_83R0_BU_idea_FM_Yoga
> > Slim 7 14ILL11.
> > Linux version 7.4.0-rc2+
> > Ubuntu 26.04.01 LTS.
> > Kernel config is copied from Ubuntu 26.04.01 LTS test kernel.
> > Lots of ACPI errors in dmesg.
> > 
> > Tried 7.3.something first, no NULL ptr dereferences, but it tried to
> > talk with some ghost rt711-sdca chip, and the sound didn't work either.
> > 7.2.x, there were some topology problems or something, apparently that
> > was fixed in the tree.
> 
> Not one I have seen before, could you re-try 7.3 but with this
> patch added:
> 
> commit e0cb731652a1bebf962086f17d1b7c9d060cb7d6
> soundwire: dmi-quirks: Disable ghost rt711 on Lenovo Yoga Slim 7
> 
> That should fix the ghost rt711 problem and would be good to see
> if this is a regression. Pretty sure it is but probably makes
> sense to confirm first.

Having a look around, I also found this patch:

https://lore.kernel.org/all/20261109102536.357134-1-ghidoliemanuele@gmail.com/

Which does sound like it fixes something that sounds very similar
to this problem. So trying that patch on top of v7.4-rc2 is also
probably a good idea.

Thanks,
Charles