gtps1m55System Macros

SPNDC-Suspend Normal CIO Processing

Use this system macro to suspend normal common input/output (CIO) processing and save any outstanding interrupts until CIO processing resumes. With the suspension of normal CIO, preemptive I/O (PIO) is activated.

While in the suspended state, it is possible to allow normal CIO processing for any pure PCI-I/O interrupts. You can do this by specifying the ALLOW parameter on the SPNDC macro. When ALLOW=PCI is specified, any queued or received PCI-only I/O interrupts are dispatched to their corresponding CIO device interrupt handler. Any device handler that expects PCI-only interrupts must be able to process while a system error dump is issued. This means that the device handler on the PCI-only path cannot use system services or try to lock any system resources because those services or resources may already be locked. The device handler should not issue any SERRC macros while processing a PCI interrupt.

Whenever ALLOW=NONE is changed to ALLOW=PCI, PIO dispatches any queued PCI-only interrupts before returning to the caller.

During IPL processing an ALLOW-IPL is supported by PIO to allow IPLB to communicate with the consoles on logical channel 0. Whenever ALLOW-IPL is specified, PIO dispatches any interrupts pending for devices on logical channel 0. Any symbolic device address (SDA) in the range 001 through 0FF is on logical channel 0. After completion of IPL processing, ALLOW=IPL is forced by PIO to ALLOW=NONE.

Format




label
A symbolic name can be assigned to the macro statement.

ALLOW
Specify one of the following:

NONE
All I/O interrupts received from CIO initiated operations will be queued for dispatch until normal CIO interrupt processing is resumed. When the ALLOW parameter is not coded, this is the default value.

PCI
Any PCI-only interrupts will be immediately dispatched to the CIO device interrupt handler. Interrupts from all other devices will be handled as described under ALLOW=NONE.

IPL
This parameter is only supported during IPL. If used after IPL, PIO will assume ALLOW=NONE. ALLOW=IPL is used by IPLB to enable and dispatch any interrupts from devices on logical channel 0.

Entry Requirements

Return Conditions

Programming Considerations

Examples

None.