Hi Keith,
I see. I thought the current CPU root complex does not support such a use case, ie removing the DPC switch device itself and might result in kernel panic. But I agree this will make the code future-proof when CPU does support such a case in the future.
Thanks for the clarification!
-Wei
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On 5/10/17, 9:17 PM, "Keith Busch" <keith.busch@xxxxxxxxx> wrote:
On Wed, May 10, 2017 at 03:39:27AM +0000, Wei Zhang wrote:
> Hi Keith and Wes,
>
> I wonder if getting an All 1’s read on the DPC status register is a
> valid scenario. The DPC register is on the switch, why would the
> status register returns All 1’s even if the device is removed?
Ah, this isn't about the downstream device precense. This is about
the DPC switch device itself, like if you pull the cable out of the
enclosure. Reading anything off the DSPs in it will see all 1's.
