Reference: http://permalink.gmane.org/gmane.comp.lib.libusbx.devel/1245
+++++++++++++ http://msdn.microsoft.com/en-us/library/windows/hardware/ff540304%28v=vs.85%29.aspx ALLOW_PARTIAL_READS (0x05) The default value is TRUE (nonzero). To disable ALLOW_PARTIAL_READS, in Value pass the address of a caller-allocated UCHAR variable set to FALSE (zero). Disabling ALLOW_PARTIAL_READS causes the read requests to fail whenever the device returns more data (on bulk and interrupt IN endpoints) than the caller requested. Enabling ALLOW_PARTIAL_READS causes WinUSB to save or discard the extra data when the device returns more data (on bulk and interrupt IN endpoints) than the caller requested. This behavior is defined by setting the AUTO_FLUSH value. ++++++++++++ >From the above, it seems to me Pete's interpretation is correct. On the other hand, somewhat I think the flag may have something to do with USBD_SHORT_TRANSFER_OK flag as well. http://msdn.microsoft.com/en-us/library/windows/hardware/ff538112(v=vs.85).aspx And the more-detailed explanation of WinUSB pipe policy is here. ++++++++++++ http://msdn.microsoft.com/en-us/library/windows/hardware/ff728833(v=vs.85).aspx ALLOW_PARTIAL_READS The device can send more data than requested. This is possible if the size of your request buffer is a multiple of the maximum endpoint packet size. Use if your application wants to read a few bytes to determine how many total bytes to read. +++++++++++ Again, the above leads to me to think that the ALLOW_PARTIAL_READS pipe policy has some linkage to USBD_SHORT_TRANSFER_OK and I am not so sure if libusbK is really at fault here. -- Xiaofan ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. ON SALE this month only -- learn more at: http://p.sf.net/sfu/learnnow-d2d _______________________________________________ libusbx-devel mailing list libusbx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libusbx-devel
