Re: Warning: mthca/qib : removal of PCI_CAP_ID_EXP

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:

quoted

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:

quoted

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<redacted>
---
    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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