Re: [PATCH v2] wifi: brcmfmac: handle missing D3 ACK on BCM4377 T2 Macs

[Arend van Spriel]

On Thu, 1 Oct 2026 10:53:08 +0200, Andre Eikmeyer wrote:
> BCM4377 on the affected T2 Macs does not acknowledge HOST_D3_INFORM.
> The current PCIe suspend callback treats this as fatal and aborts system
> suspend.
> 
> When this happens on BCM4377, mask the mailbox interrupt, preserve the
> bus-down state, and let generic PCI/ACPI suspend proceed. On resume the
> existing recovery path tears down and probes the device again instead of
> relying on a D0 mailbox transaction.
> 
> Tested-on: MacBookAir9,1, MacBookPro15,4, MacBookPro16,3
> Signed-off-by: Andre Eikmeyer <dev@deq.rocks>
> ---
>  drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c | 7 +++++++
>  1 file changed, 7 insertions(+)

Thanks for the patch. However, an earlier patch from Sebastian Reichel
already addresses this issue generically: "[wireless-next,v2] wifi: brcmfmac:
Improve D3 substate entering timeout handling" [1].

That patch makes the D3 ACK timeout non-fatal whenever Wake-on-WLAN is not
enabled, which covers BCM4377 as well and avoids the need for chip-specific
workarounds. I have accepted Sebastian's patch, so this one is superseded.

[1] https://lore.kernel.org/linux-wireless/20260915-brcmfmac-bcm43752-suspend-fix-v2-1-1bd84914998b@xxxxxxxxxxxxx/

Regards,
Arend