Re: [PATCH v2 3/3] Bluetooth: hci_bcm4377: keep ASPM off only while the firmware boots

[Sven Peter <sven@kernel.org>]

On 11/11/26 13:02, Andre Eikmeyer wrote:
> The BCM4377 needs ASPM disabled because of a hardware erratum, and the
> driver disables it on the whole link for as long as the device is bound.
> On the MacBookAir9,1 this keeps the link to the Wi-Fi and Bluetooth chip
> in L0, and the package does not go deeper than PC3.
>
> Disable ASPM only in this function's Link Control register before the
> function level reset and the firmware boot, and restore the saved value
> once the firmware runs. A non-ARI Multi-Function Device enables only the
> ASPM states enabled in all of its functions, so the link stays in L0
> until then.
>
> Tested on a MacBookAir9,1: with ASPM L1 enabled by the PCI core the link
> returns to L1 after probe and after the re-probe that follows ACPI S3,
> Bluetooth and Wi-Fi keep working, and the package reaches PC8 instead of
> PC3 at idle.
>
> Signed-off-by: Andre Eikmeyer <dev@deq.rocks>
> ---

That quirk only applies to pre-M1 machines so you probably know better 
what's required:

Acked-by: Sven Peter <sven@kernel.org>



Sven