d_mask Kernel Service

Purpose

Disables a direct memory access (DMA) channel.

Syntax

#include <sys/types.h>
#include <sys/errno.h>
#include <sys/dma.h>

void d_mask (channel_id)
int channel_id;

Parameter

Description

The d_mask kernel service disables the DMA channel specified by the channel_id parameter.

The d_mask kernel service is typically called by a device driver deallocating the resources associated with its device. Some devices require it to be used during normal device operation to control DMA requests and avoid spurious DMA operations.

Note: The d_mask service, like all DMA services, should not be called unless the d_init service has allocated the DMA channel.

Execution Environment

The d_mask kernel service can be called from either the process or interrupt environment.

Return Values

The d_mask service has no return values.

Implementation Specifics

The d_mask kernel service is part of Base Operating System (BOS) Runtime.

Related Information

The d_init kernel service, d_unmask kernel service.

I/O Kernel Services and Understanding Direct Memory Access (DMA) Transfers in AIX Version 4.3 Kernel Extensions and Device Support Programming Concepts.