I am trying to get the CCID driver to work with a bit finicky industrial device. Occasionally the communication with the device fails with error LIBUSB_TRANSFER_OVERFLOW, and then things stop working. The reason for this error is described here: https://libusb.sourceforge.io/api-1.0/libusb_packetoverflow.html

As described in the libusb doc, I was able to resolve the problem by tweaking the buffer sizes that CCID is passing to ReadPort (AKA ReadUSB) in the commands.c file. In principle, the needed tweak is to make the buffer sizes a multiple of the endpoint's wMaxPacketSize. This value can be queried from libusb. In all CCID readers I have, the value is always 64 bytes, however in the latest USB version (3.2, very unlikely to actually be used by CCID readers) it can go up to 1024 bytes if I understand correctly. So we can avoid dealing with wMaxPacketSize and just assume 1024.

Therefore, I'd like to propose rounding all buffer sizes used for USB bulk transfers to a multiple of 1024, or even just 64 if we want to use a lower value while still handling most devices, although 1024 doesn't seem high enough to me. I can send a PR if the idea is accepted.