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    SubjectRe: [PATCH 2/5] PCI: handle FLR failure and allow other reset types
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    On 10/11/2017 5:00 PM, Bjorn Helgaas wrote:
    > On Sat, Sep 23, 2017 at 08:16:55PM -0400, Sinan Kaya wrote:
    >> pci_flr_wait() and pci_af_flr() functions assume graceful return even
    >> though the device is inaccessible under error conditions.
    >>
    >> Return -ENOTTY in error cases so that __pci_reset_function_locked() can
    >> try other reset types if AF_FLR/FLR reset fails.
    >
    > This makes sense to me, but I think the error handling in
    > __pci_reset_function_locked() is confusing. It currently is:
    >
    > rc = pci_dev_specific_reset(dev, 0);
    > if (rc != -ENOTTY)
    > return rc;
    > if (pcie_has_flr(dev)) {
    > pcie_flr(dev);
    > return 0;
    > }
    > rc = pci_af_flr(dev, 0);
    > if (rc != -ENOTTY)
    > return rc;
    >
    > Would it make sense to change this to the following?
    >
    > rc = pci_dev_specific_reset(dev, 0);
    > if (rc == 0)
    > return 0;
    >
    > if (pcie_has_flr(dev)) {
    > pcie_flr(dev);
    > return 0;
    > }
    >
    > rc = pci_af_flr(dev, 0);
    > if (rc == 0)
    > return 0;
    >

    Yeah, this is cleaner. I'll create a separate patch for that.

    > I found two cases where this would make a difference: reset_ivb_igd()
    > returns -ENOMEM if pci_iomap() fails, and pci_pm_reset() returns
    > -EINVAL if the device is not in D0.
    >
    > In both cases we currently return the failure, but it would seem
    > reasonable to me to try another reset method.
    >
    > That could be done in a new patch before this one. Then *this* patch
    > could use -ETIMEDOUT instead of -ENOTTY, and I think the whole thing
    > would become a little more readable.
    >
    >> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
    >> ---


    --
    Sinan Kaya
    Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
    Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.

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