Re: CXL memory device not created correctly

From: Luis Chamberlain
Date: Tue May 30 2023 - 22:18:55 EST

On Fri, May 19, 2023 at 08:20:44AM -0700, Ira Weiny wrote:
> Davidlohr Bueso wrote:
> > On Fri, 19 May 2023, LiuLele wrote:
> >
> > >In my testing CXL device /sys/bus/cxl/devices/mem0 not created, and the get error messages :
> > >
> > >```
> > >cxl_pci 0000:0d:00.0: Failed to get interrupt for event Info log
> > >```
> > >
> > >My test environment is a qemu CXL emulator with qemu v8.0.0, Linux kernel v6.3.0.
> > >While with kernel 5.9.13, /sys/bus/cxl/devices/mem0 can be created.
> >
> > Yes, this can be annoying and would argue the probe should not error out.
> I had to double check. Events are mandatory on devices. On checking
> again interrupt support is mandatory as well. So that is why I errored
> out here.

The failure essentially creates a user visible regression whereas
booting an older kernel fixes it. It is not a friendly error message
when testing kernels / upgrading / test environments. The only thing
I can think of is if a new kconfig symbol is introduced so to make
such cases a bit more clearer for now as things get settled.

Otherwise for testing this creates a few cycles of just noise. And I'd
imagine even a few developer hours.