使用ffs从USB读取数据

发布于 2025-01-14 05:39:05 字数 763 浏览 3 评论 0原文

我面临的问题是无法从 USB 端点可靠地读取数据。我的 ffs 定义了以下 eps：

Ep0 = control
Ep1 = in
Ep2 = out

我有一个简单的 ::read() 调用，该调用在 int fd = ::open(ep1, O_RDONLY) 上被阻止。问题是，在 Ep1 上执行 ::close() 对 ::read 调用没有影响，我几乎永远被阻止。我尝试应用 select 和 poll Ep1 但这些立即返回，即使终点上没有实际数据，我后来也尝试在 Ep0 上应用 poll() 和 select() 方法，但是即使我尝试使用 WinUSB 提交数据，这些数据也会无限期地挂起。我一定错过了一些东西......不知道什么

编辑：

  int fd_control_ = ::open("/dev/usb-ffs/ABC/ep0", O_RDWR);
  int fd_read = ::open("/dev/usb-ffs/ABC/ep1", O_RDWR);

  pollfd fd;
  fd.events = POLLIN|POLLOUT;
  fd.fd = fd_control_;

  int ret = poll(&fd, 1, -1) // this never returns

  return ::read(fd_read_, buffer, bufferSize); // without the poll, ::close never release ::read()

原文

I’m facing a problem where I’m unable to reliably read data from my usb endpoints. My ffs defines the following eps:

Ep0 = control
Ep1 = in
Ep2 = out

I have a simple ::read() call that is blocked on int fd = ::open(ep1, O_RDONLY). Problem is that executing ::close() on Ep1 has no effect on the ::read call and I’m pretty much blocked forever. I tried to apply select and poll Ep1 but these returned immediately even though no actual data was present on the end point, I later on also tried to apply the poll() and select() methods on Ep0 but those hanged indefinitely even though I tried to submit data with WinUSB which also hanged up. I must be missing something… not sure what

Edit:

  int fd_control_ = ::open("/dev/usb-ffs/ABC/ep0", O_RDWR);
  int fd_read = ::open("/dev/usb-ffs/ABC/ep1", O_RDWR);

  pollfd fd;
  fd.events = POLLIN|POLLOUT;
  fd.fd = fd_control_;

  int ret = poll(&fd, 1, -1) // this never returns

  return ::read(fd_read_, buffer, bufferSize); // without the poll, ::close never release ::read()

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