RE: [PATCH] PCI Express Advanced Error Reporting Driver

[Paul Mackerras <paulus@samba.org>]

Nguyen, Tom L writes:

> The standard PCI Specification calls out SERR and PERR. I am not sure
> about the recent discussion of PCI error of recovery. It is perhaps
> regarding the possibility of recovering from a PERR or SERR. However,
> PCI Express error occurs on the PCI Express link or on behalf of
> transactions occurred on the PCI Express link. PCI Express component,
> which implements PCI Express Advanced Error Reporting Capability, sends
> error message to the Root Port to indicate error occurred on the PCI
> Express link where it is connected. The PCI Express error recovery is on
> behalf of attempting to do a PCI Express link recovery, not PCI error
> recovery. It appears that PCI Express AER is disjoint from PCI error
> recovery.

To give you some context, the recent discussion was about how we could
give a unified interface to drivers for both PCI-Express error
reporting and for the "Enhanced Error Handling" (EEH) facilities we
have on IBM PPC64 boxes.  EEH includes not only the detection and
reporting of errors (for PCI, PCI-X and PCI-Express buses) but also
hardware support for isolating devices when an error is detected, plus
means for resetting individual bus segments or slots, to assist in
recovering a device which has got into a bad state.

Does PCI Express provide any facilities for recovering from errors,
beyond just "try that transaction again"?

Paul.