User Manual

16 Specification Update
HSH26 Enabling Isochronous Transfers May Result in Unpredictable System
Behavior
Problem: Enabling isochronous transfers may lead to spurious correctable memory errors,
uncorrectable memory errors, patrol scrub errors and unpredictable system behavior.
Implication: The system may hang, or report spurious memory errors, or behave unpredictably.
Workaround: A BIOS code change has been identified and may be implemented as a workaround for
this erratum.
Status: For the affected steppings, see the Summary Tables of Changes.
HSH27 Enabling Secondary To Primary Snoop Overrides On NTB May Cause a
Hang
Problem: Due to this erratum, NTB (Non-Transparent Bridge) completions may be dropped when
Secondary to Primary Snoop Overrides are enabled.
Implication: The system may hang or experience timeout machine checks when the secondary to
primary snoop override is enabled. This erratum does not affect primary to secondary
snoop override.
Workaround: None identified. To avoid this erratum, set the bar45_s2p_snpov field (bits[7:6]) and
the bar23_s2p_snpov field (bits[3:2]) of the ntbcntl CSR (Bus: 0; Device: 3; Function:
0; Offset: 0x58) to 0.
Status: For the affected steppings, see the Summary Tables of Changes.
HSH28 Memory Controller tsod_present Settings Being Improperly Cleared
Problem: On single Home Agent configurations, due to this erratum, the processor interferes with
TSOD (thermal sensor on DIMM) usage by incorrectly clearing the tsod_present field
(bits[7:0]) of the smbcntl_1 CSR (Bus 0; Device 19; Function 0; Offset 0x198) after
BIOS writes that field.
Implication: Closed Loop Thermal Throttle will not work as expected.
Workaround: It is possible for the BIOS to contain a workaround for this erratum.
Status: For the affected steppings, see the Summary Tables of Changes.
HSH29 Reserving Resources For Isochronous Transfers With Non-Posted
Prefetching Enabled May Cause a Hang
Problem: Resources in the IIO (Integrated I/O) unit are reserved for isochronous transfers to
ensure performance guarantees are met. Due to this erratum, enabling non-posted
prefetching in the IIO when resources are reserved for isochronous traffic may result in
a hang.
Implication: Due to this erratum, configuring the IIO unit to prefetch may result in a system hang.
Workaround: A BIOS code change has been identified and may be implemented as a workaround for
this erratum.
Status: For the affected steppings, see the Summary Tables of Changes.
HSH30 BT Timeouts May Cause Spurious Machine Checks
Problem: The BT (Backup Tracker) timeout logic in the Home Agent can trigger spuriously,
causing false machine checks indicated by IA32_MCi_STATUS.MSCOD=0x0200.
Implication: Due to this erratum, timeout machine check may occur.
Workaround: It is possible for the BIOS to contain a workaround for this erratum.
Status: For the affected steppings, see the Summary Tables of Changes.