Messages in this thread | | | Subject | Re: [PATCH v9 7/8] PCI/DPC: Clear AER registers in EDR mode | From | Kuppuswamy Sathyanarayanan <> | Date | Tue, 29 Oct 2019 16:37:47 -0700 |
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On 10/29/19 3:48 PM, Bjorn Helgaas wrote: > On Tue, Oct 29, 2019 at 01:04:29PM -0700, Kuppuswamy Sathyanarayanan wrote: >> On 10/28/19 4:27 PM, Bjorn Helgaas wrote: >>> On Thu, Oct 03, 2019 at 04:39:03PM -0700, sathyanarayanan.kuppuswamy@linux.intel.com wrote: >>>> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> >>>> >>>> As per PCI firmware specification r3.2 Downstream Port Containment >>>> Related Enhancements ECN, >>> Specific reference, please, e.g., the section/table/figure of the PCI >>> Firmware Spec being modified by the ECN. >> Ok. I will include it. >>>> OS is responsible for clearing the AER >>>> registers in EDR mode. So clear AER registers in dpc_process_error() >>>> function. >>>> >>>> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> >>>> Acked-by: Keith Busch <keith.busch@intel.com> >>>> --- >>>> drivers/pci/pcie/dpc.c | 4 ++++ >>>> 1 file changed, 4 insertions(+) >>>> >>>> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c >>>> index fafc55c00fe0..de2d892bc7c4 100644 >>>> --- a/drivers/pci/pcie/dpc.c >>>> +++ b/drivers/pci/pcie/dpc.c >>>> @@ -275,6 +275,10 @@ static void dpc_process_error(struct dpc_dev *dpc) >>>> pci_aer_clear_fatal_status(pdev); >>>> } >>>> + /* In EDR mode, OS is responsible for clearing AER registers */ >>>> + if (dpc->firmware_dpc) >>> I guess "EDR mode" is effectively the same as "firmware-first mode"? >> Yes, EDR mode is an upgrade to FF mode in which firmware allows OS >> to share some of it job by sending ACPI notification. If you don't >> get ACPI notification, EDR mode is effectively same as FF mode. May be I can add some documentation in code to explain the EDR mode better. > Hmm, somehow the connection between FF and EDR needs to be clear from > the code, so people who weren't involved in the development of EDR and > don't even have access to the specs/ECNs can make sense out of this. > >>> At least, the only place we set "firmware_dpc = 1" is: >>> >>> + if (pcie_aer_get_firmware_first(pdev)) >>> + dpc->firmware_dpc = 1; >>> >>> If they're the same, why do we need two different names for it? >> For better readability and performance, I tried to cache the value of >> pcie_aer_get_firmware_first() result in DPC driver. > pcie_aer_get_firmware_first() already caches the value, so I don't > think you're gaining any useful performance here, and having two > different names *decreases* readability. Ok. I can replace "firmware_dpc" with pcie_aer_get_firmware_first() calls. > > I do agree that pcie_aer_get_firmware_first() is not optimally > implemented. I think we should probably look up the firmware-first > indication explicitly during enumeration so we don't have to bother > with the dev->__aer_firmware_first_valid thing. And if we got rid of > all those leading underscores, it would probably run faster, too ;) I agree that pcie_aer_get_firmware_first() can be optimized. I can submit a patch for it once this patch set is merged. > >>>> + pci_cleanup_aer_error_status_regs(pdev); >>>> + >>>> /* >>>> * Irrespective of whether the DPC event is triggered by >>>> * ERR_FATAL or ERR_NONFATAL, since the link is already down, >>>> -- >>>> 2.21.0 >>>> >> -- >> Sathyanarayanan Kuppuswamy >> Linux kernel developer >> -- Sathyanarayanan Kuppuswamy Linux kernel developer
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