Re: [PATCH 0/3] ACPI: Serialize battery methods and INT3403 _TMP

[Rong Zhang]

Hi Ali,

Thanks for working on this!

The series is generally in a good shape. I just have a few minor
comments.

On Wed, 2026-10-14 at 16:26 +0300, Ali Ahmet Memiş wrote:
> As discussed in [1], add exclusive variants of acpi_evaluate_object()
> and acpi_evaluate_integer() and use them for the battery methods and
> INT3403 _TMP, which interleave badly on ThinkPad P1 Gen2 and P53.
> 
> UCSI (bko221065) is not converted.  
> 

Please leave a link to the bko bug, so that readers don't need to
assemble the link themselves.

> There the contention is on a

After carefully auditing the ASL code again, I've just found the root
cause of the mutex acquisition timeout.

It's hard to notice, but \_SB.PCI0.LPC0.EC0.RDER being declared as
"Serialized" causes an ABBA deadlock:

Thread 1 (battery)                         Thread 2 (ideapad-laptop)
-----------------------------------------  ---------------------------------------
serialize \_SB.BAT0._BIX                   serialize \_SB.PCI0.LPC0.EC0.VPC0.GBMD
evaluate \_SB.BAT0._BIX                    evaluate \_SB.PCI0.LPC0.EC0.VPC0.GBMD
  acquire ECMT [A]
  serialize \_SB.PCI0.LPC0.EC0.RDIF          serialize \_SB.PCI0.LPC0.EC0.RDER [B]
  evaluate \_SB.PCI0.LPC0.EC0.RDIF           evaluate \_SB.PCI0.LPC0.EC0.RDER
    serialize \_SB.PCI0.LPC0.EC0.RDER [B]      acquire ECMT [A]

That's why merging battery notifications significantly reduced the
frequency of mutex acquisition timeout.

> firmware AML mutex that _Qxx EC queries also take, which a wrapper
> around acpi_evaluate_object() cannot cover, and Rong's notification
> merging in 7.3 already reduces it on the battery side.

Lock contention is not the root cause, and EC queries and UCSI _DSM are
just innocent victims of the ABBA deadlock.

Please rephrase the cover letter accordingly.

> 
> [1] https://lore.kernel.org/all/CAJZ5v0gS4agVUkCO6M=VW4Wi2y1-s+k23bpzmX9aAZ0Rsv4z9Q@xxxxxxxxxxxxxx/

You can use Link: tags in the cover letter, e.g.:

Link: https://lore.kernel.org/all/CAJZ5v0gS4agVUkCO6M=VW4Wi2y1-s+k23bpzmX9aAZ0Rsv4z9Q@xxxxxxxxxxxxxx/ [1]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=221065

Thanks,
Rong

> 
> Ali Ahmet Memiş (3):
>   ACPI: utils: Add exclusive AML evaluation helpers
>   ACPI: battery: Evaluate battery methods exclusively
>   thermal: intel: int340x: Evaluate _TMP exclusively
> 
>  drivers/acpi/battery.c                        | 17 +++---
>  drivers/acpi/utils.c                          | 56 +++++++++++++++++--
>  .../int340x_thermal/int340x_thermal_zone.c    |  3 +-
>  include/acpi/acpi_bus.h                       |  8 +++
>  4 files changed, 71 insertions(+), 13 deletions(-)
> 
> 
> base-commit: 24a19b953e2a3d0ea5a8c4951a0ab8f32720c907