Re: Maximum transfer size when call bulk transfer API in libusb

Thanks for your answer.


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On Fri, Oct 16, 2015 at 7:34 PM -0700, "Xiaofan Chen" <[email protected]> wrote:
On Fri, Oct 16, 2015 at 10:25 AM, ZhangHua <[email protected]> wrote:
> Hi,
>
> I'm using https://github.com/libusb and based on libusbK.sys. Per MS's link:
> https://msdn.microsoft.com/en-us/library/windows/hardware/ff538112%28v=vs.85%29.aspx?f=255&MSPPError=-2147217396.
> It has hard-coded limit in there USB driver stack. Then what libusbK.sys and
> libusb done for this? If I need split my large chunks of data to smaller
> ones then call "libusb_bulk_transfer"? Or MS or libusb or libusbK have done
> the data *scaling* at lower layer for user?
>

Firstly this mailing list is for libusb-win32 and not libusb. So you may
want to subscribe to the correct libusb mailing list here.
   https://lists.sourceforge.net/lists/listinfo/libusb-devel

libusb Website:
http://libusb.info/
https://github.com/libusb/libusb/wiki

Anyway, in general you do not need to worry, libusb and the Windows
driver stack will split the things for you.

The only exception may be Control Transfer. There you have a hard
limit of 4096 bytes for libusb under Windows and Linux.

Interestingly I do not see such limitation in libusb-win32 of
control transfer from the source code.

--
Xiaofan

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