Re: [PATCH v9 5/8] PCI/AER: Allow clearing Error Status Register in FF mode

[Kuppuswamy Sathyanarayanan]

On 10/29/19 4:03 PM, Bjorn Helgaas wrote:
> On Tue, Oct 29, 2019 at 12:58:14PM -0700, Kuppuswamy Sathyanarayanan wrote:
> > On 10/28/19 4:22 PM, Bjorn Helgaas wrote:
> > > On Thu, Oct 03, 2019 at 04:39:01PM -0700, sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx wrote:
> > > > From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> > > > @@ -430,9 +424,6 @@ int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
> > > >    	if (!pos)
> > > >    		return -EIO;
> > > > -	if (pcie_aer_get_firmware_first(dev))
> > > > -		return -EIO;
> > > > -
> > > >    	port_type = pci_pcie_type(dev);
> > > >    	if (port_type == PCI_EXP_TYPE_ROOT_PORT) {
> > > >    		pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, &status);
> > > > @@ -455,7 +446,8 @@ void pci_aer_init(struct pci_dev *dev)
> > > >    	if (dev->aer_cap)
> > > >    		dev->aer_stats = kzalloc(sizeof(struct aer_stats), GFP_KERNEL);
> > > > -	pci_cleanup_aer_error_status_regs(dev);
> > > > +	if (!pcie_aer_get_firmware_first(dev))
> > > > +		pci_cleanup_aer_error_status_regs(dev);
> > > This effectively moves the "if (pcie_aer_get_firmware_first())" check
> > > from pci_cleanup_aer_error_status_regs() into one of the callers.  But
> > > there are two other callers: pci_aer_init() and pci_restore_state().
> > > Do they need the change, or do you want to cleanup the AER error
> > > registers there, but not here?
> > Good catch. I have added this check to pci_aer_init(). But it needs
> > to be added to pci_restore_state() as well. Instead of moving the
> > checks to the caller, If you agree, I could change the API to
> > pci_cleanup_aer_error_status_regs(struct pci_dev *dev, bool
> > skip_ff_check) and let the caller decide whether they want skip the
> > check or not.
> If all callers of pci_cleanup_aer_error_status_regs() would have to
> check pcie_aer_get_firmware_first(), I don't understand why you're
> moving the check at all.

We need exception for the call made from DPC driver. If 
pcie_aer_get_firmware_first()
call is made from DPC driver during EDR mode execution, then FF mode 
check needs
to be skipped.

>
--
Sathyanarayanan Kuppuswamy
Linux kernel developer