Multi Channel DMA Intel® FPGA IP for PCI Express User Guide

ID 683821
Date 4/20/2022
Public

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Document Table of Contents

8.3.3.3.2. Poll Mode

  • In Poll mode, poll system call is called on the character device node
  • Kernel module uses 2 flags as return values to pass the current state of each descriptor queue of the channel
  • POLLIN/POLLOUT: Indicates whether there exists at least one available slot in the descriptor queue
  • POLLRDNORM/POLLWRNORM: Indicates whether the descriptor queue is empty or not
  • Polling also increases the eventfd counter using eventfd_signal API