Re: [PATCH V12 4/9] cxl/pci: Create PCI DOE mailbox's for memory devices

[Davidlohr Bueso]

On Thu, 30 Jun 2022, Jonathan Cameron wrote:

> On Wed, 29 Jun 2022 22:32:57 -0700 Ira Weiny <ira.weiny@xxxxxxxxx> wrote:

> > I _thought_ that we did not care if some mailboxes failed or not.
>
> I have a different view to Dan on this.  In my view if your hardware is
> not working in any way at all scream like mad don't carry on... Dan
> is keen to try to muddle onwards.

I am also of the idea of not carrying on upon any indication of failure.

> > If CDAT is not supported on any of the mailboxes found then CDAT will not show
> > up on sysfs (as per Dan's last comment).  If it was supported on a mailbox but
> > no data is found the sysfs will show up but be 0 length.
> >
> > At this layer I thought we agreed to skip over these errors.  If a protocol is
> > needed at a higher layer and it is not found on any of the mailboxes the errors
> > should show up in that layer.  In this series CDAT is not 100% necessary as
> > devices can work without it.  So the errors were mostly paper'ed over in favor
> > of just printing error messages and muddle on.
> >
> > The xa_insert() deserves a pci_err() though.
>
> That's probably the minimum we should do.  The xa_insert() failing is something
> horrible going wrong in our software / host afterall.

Yes. And in addition, devm_cxl_pci_create_doe() should return any error status, and
cxl_pci_probe() can choose to omit any errors, but it's still better to have it.

Thanks,
Davidlohr