On 5/27/21 11:32 AM, Lorenzo Pieralisi wrote:
On Wed, May 26, 2021 at 09:58:36PM +0100, Will Deacon wrote:
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@xxxxxxxxx>
---
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@xxxxxxxxx
Sigh. We can't apply this patch since it would trigger regressions on
other platforms (IIUC the root complex registers would end up in the
host bridge memory windows).
I am not keen on reverting commit 8fd4391ee717 because it does the
right thing.
I think this requires a quirk and immediate reporting to Microsoft.
Since I wrote this I have found other arm64 devices with the same
problem. I don't think that this is Microsoft exclusive anymore, but
rather that this is a Qualcomm problem (Qualcomm SoC seems to be the
common thread). See e.g. DSDTs in [1]. So it should probably be reported
to them.
Regards,
Max
[1]: https://github.com/aarch64-laptops/build/tree/dfce25bc12655713c7e1e0422b191e9c944e4fb2/misc
