Re: Warning: iwlegacy/iwlwifi/rtlwifi : removal of PCI_CAP_ID_EXP

[James Smart <james.smart@emulex.com>]

FYI:   after discussion of this error on linux-pci and linuxppc-dev, the error 
was corrected in a patch checked into 2.6.33-rc6/3.0-rc6 
(http://marc.info/?l=linux-pci&m=130992047232053&w=2)

-- james s




On 7/1/2011 10:49 AM, James Smart wrote:
> All,
>
> I wanted to communicate a potential warning to those drivers that had a patch
> submitted to replace config space searches of PCI_CAP_ID_EXP with shorthand
> options such as is_pcie and pci_is_pcie().
>
> Testing with the lpfc driver and AER/EEH identified cases where the short-hand
> search options would fail on PPC platforms.  The only successful option in all
> cases was the explicit search via PCI_CAP_ID_EXP.   Therefore, I recommend
> that this change not be accepted until the platform level issue can be
> identified and corrected.
>
> -- james s
>
>
>
> On 6/30/2011 4:41 PM, James Smart wrote:
>> Jon,
>>
>> I must NACK this patch to the lpfc driver and recommend that all other patches
>> which replace pci_find_capability(pdef, PCI_CAP_ID_EXP) with
>> "pci_is_pcie(pdev)" are NACK'd as well.
>>
>> The reason is due to an issue on PPC platforms whereby use of "pdev->is_pcie"
>> and pci_is_pcie() will erroneously fail under some conditions, but explicit
>> search for the capability struct via pci_find_capability() is always
>> successful.   I expect this to be due a shadowing of pci config space in the
>> hal/platform that isn't sufficiently built up.  We detected this issue while
>> testing AER/EEH, and are functional only if the pci_find_capability() option
>> is used.
>>
>> -- james s
>>
>>
>>
>> On 6/27/2011 1:39 PM, Jon Mason wrote:
>>> The PCIE capability offset is saved during PCI bus walking.  It will
>>> remove an unnecessary search in the PCI configuration space if this
>>> value is referenced instead of reacquiring it.  Also, pci_is_pcie is a
>>> better way of determining if the device is PCIE or not (as it uses the
>>> same saved PCIE capability offset).
>>>
>>> Signed-off-by: Jon Mason<jdmason@kudzu.us>
>>> ---
>>>     drivers/scsi/lpfc/lpfc_init.c |    2 +-
>>>     1 files changed, 1 insertions(+), 1 deletions(-)
>>>
>>> diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
>>> index 148b98d..9000ad0 100644
>>> --- a/drivers/scsi/lpfc/lpfc_init.c
>>> +++ b/drivers/scsi/lpfc/lpfc_init.c
>>> @@ -3970,7 +3970,7 @@ lpfc_enable_pci_dev(struct lpfc_hba *phba)
>>>     	pci_save_state(pdev);
>>>
>>>     	/* PCIe EEH recovery on powerpc platforms needs fundamental reset */
>>> -	if (pci_find_capability(pdev, PCI_CAP_ID_EXP))
>>> +	if (pci_is_pcie(pdev))
>>>     		pdev->needs_freset = 1;
>>>
>>>     	return 0;
>> --
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>