In order to allow for sending feature reports to my device in Windows, I am using the following special HID report in my USB device. It lets me use hidapi's set_feature_request / get_feature_request from userspace programs on report ID 0xAA... And works great, but I want more!
In Linux, I can send "up to" 254 payload bytes, but in Windows I must send exactly 254 bytes. Is there a way of specifying that I want the size to be variable, and not fixed to exactly 254 bytes but allow up-to 254 bytes or a range.
static const uint8_t special_hid_desc[] = {
HID_USAGE_PAGE ( HID_USAGE_PAGE_DESKTOP ),
HID_USAGE ( 0x00 ),
HID_REPORT_SIZE ( 8 ),
HID_COLLECTION ( HID_COLLECTION_LOGICAL ),
HID_REPORT_COUNT ( 254 ),
HID_REPORT_ID ( 0xaa )
HID_USAGE ( 0x00 ),
HID_FEATURE ( HID_DATA | HID_VARIABLE | HID_ABSOLUTE ) ,
HID_COLLECTION_END
};