Re: [PATCH v2] PCI/AER: enable SERR# forwarding for bridges and switches

[Sinan Kaya <okaya@codeaurora.org>]

On 12/28/2015 5:29 PM, Bjorn Helgaas wrote:
> Hi Sinan,
> 
> Sorry for the delay in responding; I was on vacation when you sent
> this, and I missed it when I returned.
> 
> On Mon, Dec 14, 2015 at 01:22:39PM -0500, Sinan Kaya wrote:
>> On 12/11/2015 6:30 PM, Sinan Kaya wrote:
>>>> I think the best way to fix all the cases would be to do something in
>>>>> in pci_configure_device().  Then we could drop the AER bus walk in
>>>>> set_downstream_devices_error_reporting().  A bus walk like that is
>>>>> always an issue for hotplug.
>>>>>
>>> Let me read some code.
>>
>> OK, If I understand it right; pci_configure_device is where
>> program_hpp_type0 called. You also want to enable AER in this function.
>>
>> Move the contents of set_device_error_reporting into
>> pci_configure_device like this below ?
>>
>> ...
>> + int type = pci_pcie_type(dev);
>>
>> pci_configure_mps(dev);
>>
>> +	if ((type == PCI_EXP_TYPE_ROOT_PORT) ||
>> +	    (type == PCI_EXP_TYPE_UPSTREAM) ||
>> +	    (type == PCI_EXP_TYPE_DOWNSTREAM)) {
>> +		pci_enable_pcie_error_reporting(dev);
>> +	}
>>
>> +	pcie_set_ecrc_checking(dev);
> 
> Yep, that's the sort of thing I'm thinking.
> 
> I think there are some subtleties to consider.
> 
> _HPP/_HPX can twiddle some of the same bits.  Should we allow _HPP to
> clear a bit that pci_enable_pcie_error_reporting() would set?  What
> about the reverse?
> 
> There are a ridiculous number of places that call
> pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR).  We should
> do it once and cache the result in struct pci_dev.
> 
> Bjorn
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> 

Thanks for the heads up. I had another pending question to you on another patch.
I just sent a ping. 

I'll start working on this patch after the holidays.




-- 
Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project