Re: [PATCH v16 5/7] spi: pxa2xx: disable DMA for Apple MacBook8,1

[Andy Shevchenko]

On Tue, Jul 21, 2026 at 11:26:27PM +0800, Shih-Yuan Lee (FourDollars) wrote:
> On Tue, Jul 21, 2026 at 11:05 PM Mark Brown <broonie@xxxxxxxxxx> wrote:

...

> Actually, I was just following Lukas's suggestion to modify
> drivers/dma/dw/pci.c to do a quick proof-of-concept test, and I used
> an AI assistant to help me write and deploy the driver quirk code.
> 
> I have previous experience with the Initrd ACPI Table Override
> mechanism, so I can definitely try that on my machine next to see if
> we can get DMA working properly by aligning the PCI routing and DMAR
> mapping correctly).
> output.

For old hardware (before Skylake) LPSS DMA interrupt line is defined in
two places: DSDT (and/or PCI) and CSRT. Changing in one might not help
as CSRT may have something different. Check drivers/dma/acpi-dma.c
acpi_dma_parse_resource_group().

-- 
With Best Regards,
Andy Shevchenko