Re: [PATCH 2/2] pci: Add ignore indicator quirk for devices

[Keith Busch <keith.busch@intel.com>]

On Mon, Aug 22, 2016 at 11:55:24AM -0500, Bjorn Helgaas wrote:
> I was imagining these LEDs as some sort of extension to the PCIe
> hotplug model, but I think that was a mistake: logically, they have
> nothing to do with hotplug, and the only reason they're currently
> associated with hotplug is because you chose to re-use a bus (VPP)
> that happens to be connected to the Slot Control registers.
> 
> From an architectural point of view, these LEDs seem device-specific
> or storage-specific, with no connection to PCIe at all, so I don't
> know why we would put them in the PCIe spec or teach pciehp about
> them.

It's not entirely for hotplug scenarios, but it does help with user pain
points locating devices they intend to hot remove.

I hear many vendors are for the concept of proposing new status
and location indicator definitions to PCIe. I don't think anyone is
suggesting the implementation requiring this patch be made standard;
this generation of hardware is just a non-standard implementation that
needs a quirk to help fill the gap.

Would it be more palatable if I modify the quirk such that when set,
pciehp provides a sysfs entry allowing arbitrary user defined Slot Control
commands? That removes the dangerous direct access from user space.