Down Turbo Vortex Errors - DEC AlphaServer 8200 Technical Manual

The ICR up Turbo Vortex interface checks for the following types of errors:
Reporting of up Turbo Vortex detected errors can be enabled by setting
ICCNSE<INTR_NSES>, which results in the I/O port posting an IPL 17
interrupt. In addition to posting an interrupt, the ICR transmits a
UTV_ERROR_A (or B) command across the I/O port's internal command
bus to each of the IDRs. This causes the buffer pointers for the up Turbo
Vortex transaction buffers to be incremented to the next buffer. Once the
processing of the transaction has been completed, a DECR_PKT signal is
asserted from the ICR to the HDR, keeping the buffer counters in sync be-
tween the two chips.
The IDR up Turbo Vortex interface checks for the following types of er-
rors:
The detection of up Turbo Vortex errors by the IDRs is logged by setting
IDPNSE<IDR_UP_VRTX_ERROR>. If the error is detected by IDR1 on
the first up Turbo Vortex cycle, then the transaction is not initiated.
If the up Turbo Vortex error is detected by IDR0, IPD2, or IDR3, or if the
error is detected on the second or subsequent cycle by IDR1, then the data
is tagged as bad and the transaction is initiated. When the tagged data is
to be written to the TLSB, the bus is defaulted instead. Note that this re-
sults in an uncorrectable ECC error on the TLSB, with the I/O port as the
transmitter during error. This is in addition to the up Turbo Vortex error
indication in the IDPNSEn register.

6.7.10.3 Down Turbo Vortex Errors

Error checking is implemented on the down Turbo Vortex interface in the
HDR gate array. Handling of errors by the down HDR is packet depend-
ent. If the error is detected on a Mailbox Command packet, interrupt
status packet, or an unknown packet type, the packet is discarded. If the
error is detected on a packet that is determined to be DMA read return
data, then a DMA read return with error packet is sent down the hose.
The following down Turbo Vortex errors can be detected by the HDR:
Reporting of down Turbo Vortex errors is accomplished through the asser-
tion of a down Turbo Vortex error signal from the HDR to the ICR. The
6-76 I/O Port
• Parity errors
• Sequence errors
• Buffer overflow errors
• Illegal command errors
• Parity errors
• Overflow errors
• Sequence errors
• Parity errors
• Sequence errors
• Buffer overflow errors
• Internal HDR errors