libusb批量的最大传输大小是多少

Question

最近我正在开发一个在Linux上运行的自定义USB接收器程序。我选择使用libusb来开发它。由于带宽更大，我需要更大的总传输大小。当时，当我提交超过15MB(每次批量传输1MB，第16次提交失败(时，会出现错误：

[INFO] submit transfer [0]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[INFO] submit transfer [1]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[INFO] submit transfer [2]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[INFO] submit transfer [3]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[INFO] submit transfer [4]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[INFO] submit transfer [5]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[INFO] submit transfer [6]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[INFO] submit transfer [7]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[INFO] submit transfer [8]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[INFO] submit transfer [9]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[INFO] submit transfer [10]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[INFO] submit transfer [11]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[INFO] submit transfer [12]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[INFO] submit transfer [13]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[INFO] submit transfer [14]: [0] LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
libusb: error [submit_bulk_transfer] submiturb failed error -1 errno=12
[INFO] submit transfer [15]: [-1] LIBUSB_ERROR_IO
libusb: error [submit_bulk_transfer] submiturb failed error -1 errno=12

这是ubuntu18.04，上的测试结果

相关系统信息：

Linux xxx 5.4.0-77-generic #86~18.04.1-Ubuntu SMP Fri Jun 18 01:23:22 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

系统RAM:20GB

当我在树莓派4B上测试它时，我也遇到了同样的问题。我没有通过谷歌找到相关问题的答案(可能使用了错误的关键词？(

这里有一个非常相似的问题，但他说，最大极限是int可以表示的最大值，但事实似乎并非如此。

任何建议或暗示都会对我有很大帮助！

Answer 1

事实证明，我使用谷歌很糟糕，开源真的很棒！！

我深入研究了代码，在内核源代码中发现了内存限制：https://github.com/torvalds/linux/blob/3d5895cd351757f69c9a66fb5fc8cf19f454d773/drivers/usb/core/devio.c#L133

现在我可以通过/sys/module/usbcore/parameters/usbfs_memory_mb设置内存限制