Re: [PATCH v3 2/2] PCI/AER: Enable AER on all PCIe devices supporting it

[Bjorn Helgaas <helgaas@kernel.org>]

On Thu, Jan 20, 2022 at 08:31:31AM +0100, Stefan Roese wrote:
> On 1/19/22 11:37, Pali Rohár wrote:

> > And when you opened this issue with hotplugging, another thing for
> > followup changes in future is calling pcie_set_ecrc_checking() function
> > to align ECRC state of newly hotplugged device with "pci=ecrc=..."
> > cmdline option. As currently it is done only at that function
> > set_device_error_reporting().
> 
> Agreed, this is another area to look into. Not sure if it's okay to
> address this, once this patch-set has been accepted (if it will be).

ECRC might be something that could be peeled off first to reduce the
complexity of AER itself.

The ECRC capability and enable bits are in the AER Capability, so I
think it should be moved to pci_aer_init() so it happens for every
device as we enumerate it.

As far as I can tell, there is no requirement that every device in the
path support ECRC, so it can be enabled independently for each device.
I think devices that don't support ECRC checking must handle TLPs with
ECRC without error.

Per Table 6-5, ECRC check failures result in a device logging the
prefix/header of the TLP and sending ERR_NONFATAL or ERR_COR.  I think
this is useful regardless of whether AER interrupts are enabled
because error information is logged where the ECRC failure was
detected.

Bjorn