On Tue, May 11, 2021 at 01:40:20AM +0200, Maximilian Luz wrote:

The Microsoft Surface Pro X has host bridges defined as

    Name (_HID, EisaId ("PNP0A08") /* PCI Express Bus */)  // _HID: Hardware ID
    Name (_CID, EisaId ("PNP0A03") /* PCI Bus */)  // _CID: Compatible ID

    Method (_CRS, 0, NotSerialized)  // _CRS: Current Resource Settings
    {
        Name (RBUF, ResourceTemplate ()
        {
            Memory32Fixed (ReadWrite,
                0x60200000,         // Address Base
                0x01DF0000,         // Address Length
                )
            WordBusNumber (ResourceProducer, MinFixed, MaxFixed, PosDecode,
                0x0000,             // Granularity
                0x0000,             // Range Minimum
                0x0001,             // Range Maximum
                0x0000,             // Translation Offset
                0x0002,             // Length
                ,, )
        })
        Return (RBUF) /* \_SB_.PCI0._CRS.RBUF */
    }

meaning that the memory resources aren't (explicitly) defined as
"producers", i.e. host bridge windows.

Commit 8fd4391ee717 ("arm64: PCI: Exclude ACPI "consumer" resources from
host bridge windows") introduced a check that removes such resources,
causing BAR allocation failures later on:

    [ 0.150731] pci 0002:00:00.0: BAR 14: no space for [mem size 0x00100000]
    [ 0.150744] pci 0002:00:00.0: BAR 14: failed to assign [mem size 0x00100000]
    [ 0.150758] pci 0002:01:00.0: BAR 0: no space for [mem size 0x00004000 64bit]
    [ 0.150769] pci 0002:01:00.0: BAR 0: failed to assign [mem size 0x00004000 64bit]

This eventually prevents the PCIe NVME drive from being accessible.

On x86 we already skip the check for producer/window due to some history
with negligent firmware. It seems that Microsoft is intent on continuing
that history on their ARM devices, so let's drop that check here too.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
---

Please note: I am not sure if this is the right way to fix that, e.g. I
don't know if any additional checks like on IA64 or x86 might be
required instead, or if this might break things on other devices. So
please consider this more as a bug report rather than a fix.

Apologies for the re-send, I seem to have unintentionally added a blank
line before the subject.

---
 arch/arm64/kernel/pci.c | 14 --------------
 1 file changed, 14 deletions(-)

Adding Lorenzo to cc, as he'll have a much better idea about this than me.

This is:

https://lore.kernel.org/r/20210510234020.1330087-1-luzmaximilian@gmail.com (local)

Will

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