Specification Update

18 Intel
®
E7320 Memory Controller Hub (MCH) Specification Update
Errata
Custom operating systems or future operating systems that independently manage the power state
of PCI Express devices outside the scope of system power state transitions would be similarly
exposed to link-down errors via the same mechanism. In cases where the destination power state on
the attached device is between D0 and D3, any such link-down event constitutes a real error from
which software may only recover by fully reconfiguring the devices below the affected link.
Workaround: None
Status: For the steppings affected, see the Summary Table of Changes.
28. Possible loss of Hot-swap Power Fault Event in dual PCI Express Hot-swap
port configurations
Problem: During boot, as part of normal PCI enumeration, the external hot-swap expander device on the PCI
Express hot-swap ports must be configured. This PCI enumeration proceeds on a per device basis,
during which an expander input change on the second port might get lost. There is sufficient time
between configuration of the first PCI Express hot-swap port and the second port for this erratum
to happen, due to interaction between the internal hot-swap controller and the external hot-swap
expander.
Implication: A power fault event, as an example, could occur on the second port before it was configured. The
power fault event is thus not reported.
Workaround: Force the configuration of both hot-swap controllers to occur back-to-back in time. This prevents
any controller/expander traffic other than the configuration until both expanders have been
configured, and ensures that the controller and the external expander are in agreement. In BIOS,
make sure that setting the hot-swap capable bit for one of the hot-swap ports is followed
immediately by setting the same bit for the other hot-swap port.
Status: For the steppings affected, see the Summary Table of Changes.