Re: [PATCH v2] PCI: add support for Immediate Readiness

[Felipe Balbi <felipe.balbi@linux.intel.com>]

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Bjorn Helgaas <helgaas@kernel.org> writes:

> On Fri, Sep 07, 2018 at 09:16:51AM +0300, Felipe Balbi wrote:
>> PCIe GEN4 defines, on section 7.5.1.1.4, a new bit on Status Register
>> which tells us that:
>> 
>> "Immediate Readiness – This optional bit, when Set, indicates the
>> Function is guaranteed to be ready to successfully complete valid
>> configuration accesses at any time following any reset that the host
>> is capable of issuing Configuration Requests to this Function.
>> 
>> When this bit is Set, for accesses to this Function, software is
>> exempt from all requirements to delay configuration accesses following
>> any type of reset, including but not limited to the timing
>> requirements defined in Section 6.6.  How this guarantee is
>> established is beyond the scope of this document.
>> 
>> It is permitted that system software/firmware provide mechanisms that
>> supersede the indication provided by this bit, however such
>> software/firmware mechanisms are outside the scope of this
>> specification."
>> 
>> This means that all delays after a Conventional or Function Reset can
>> be skipped.
>> 
>> This patch reads such bit and caches its value in a flag inside struct
>> pci_dev to be checked later if we should delay or can skip delays
>> after a reset. While at that, also move the explicit msleep(100) call
>> from pcie_flr() and pci_af_flr() to pci_dev_wait().
>> 
>> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
>
> Applied to pci/enumeration for v4.20, thanks!

Thank you

-- 
balbi

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