Re: [REGRESSION] applespi from 6.12 onwards

On Thu, May 08, 2025 at 10:15:31AM +0800, Baolu Lu wrote:

On 5/8/25 01:07, Aditya Garg wrote:

quoted

Keyboard and touchpad stopped working on several Apple Macbooks from the year 2017 using kernel 6.12.xx . Until now I could only find this discussion affirming the bug on Debian and Fedora:https://github.com/Dunedan/mbp-2016-linux/issues/202

On siduction I also tried the more recent kernels 6.14.5 and mainline 6.15-rc4 (from Ubuntu) and the issue persisted with my testdevice MacBookPro14,1 -- see the relevant output:

kernel: platform pxa2xx-spi.3: Adding to iommu group 20
kernel: input: Apple SPI Keyboard as /devices/pci0000:00/0000:00:1e.3/pxa2xx-spi.3/spi_master/spi2/spi-APP000D:00/
input/input0
kernel: DMAR: DRHD: handling fault status reg 3
kernel: DMAR: [DMA Read NO_PASID] Request device [00:1e.3] fault addr 0xffffa000 [fault reason 0x06] PTE Read access is not set
kernel: DMAR: DRHD: handling fault status reg 3
kernel: DMAR: [DMA Read NO_PASID] Request device [00:1e.3] fault addr 0xffffa000 [fault reason 0x06] PTE Read access is not set
kernel: applespispi-APP000D:00: Error writing to device: 01 0e 00 00
kernel: DMAR: DRHD: handling fault status reg 3
kernel: DMAR: [DMA Read NO_PASID] Request device [00:1e.3] fault addr 0xffffa000 [fault reason 0x06] PTE Read access is not set
kernel: DMAR: DRHD: handling fault status reg 3
kernel: applespispi-APP000D:00: Error writing to device: 01 0e 00 00

It appears that all DMA faults are related to a fixed address,
0xffffa000. Is this address something special?

Also what does below message mean from a SPI driver's perspective?

"applespispi-APP000D:00: Error writing to device: 01 0e 00 00"

I am asking this because the IOMMU fault messages are about DMA Reads
(device raised memory read), while above message complains failing to
write to device.

When sending a command to the peripheral device applespi expects it to
acknowledge successful transfer with

	static u8 status_ok[] = { 0xac, 0x27, 0x68, 0xd5 };

but we are getting "01 0e 00 00" instead.

See applespi_check_write_status() in drivers/input/Keyboard/applespi.c

Thanks.

-- 
Dmitry