Re: [GIT PULL] PCI changes for v4.20

[Lendacky, Thomas]

On 11/13/2018 04:20 AM, Borislav Petkov wrote:
> On Tue, Nov 13, 2018 at 08:17:12AM +0100, Ingo Molnar wrote:
>>
>> * Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote:
>>
>>> PCI changes:
>>>
>>>   - Pay attention to device-specific _PXM node values (Jonathan Cameron)
>>
>> There's a new boot regression, my AMD ThreadRipper system (MSI X399 SLI 
>> PLUS (MS-7B09)) hangs during early bootup, and I have bisected it down to 
>> this commit:
>>
>>   bad7dcd94f39: ACPI/PCI: Pay attention to device-specific _PXM node values
>>
>> Reverting it solves the hang.
>>
>> Unfortunately there's no console output when it hangs, even with 
>> earlyprintk. It just hangs after the "loading initrd" line.
>>
>> Config is an Ubuntu-ish config with PROVE_LOCKING=y and a few other debug 
>> options.
>>
>> All my other testsystems boot fine with similar configs, so it's probably 
>> something specific to this system.
> 
> Lemme add Tom, he might have an idea.

I'm not seeing any issues on my EPYC system.  Let me see if I can locate a
Threadripper system to test on.

It seems very strange that the commit in question would cause a hang so
early. Do you have a serial console hooked up for the earlyprintk? Is the
serial port set up in legacy mode (e.g. 0x3f8 as opposed to being an MMIO
device that would require a driver)?

Can you dump the ACPI tables / run them through iasl to see what the _PXM
values are in the DSDT table?

Thanks,
Tom

>