Hi,
This is a follow up to some HID communication questions that I have posted
earlier. It relates to use of libhid, but may also be tied to how HID/USB
communication is handled in Linux (Ubuntu in particular). Since I am relatively
new to both, any pointers I get will be much appreciated.
The device in question is a composite USB memory token that also enumerates as
an HID device. It has four end points; ep 1 and ep 2 for bulk mass storage, ep
0 as control end-point, and ep 4 for interrupt IN. The control end-point is
used for sending HID data from host to device, and the interrupt end-point for
sending HID data from device to the host.
I can talk to this device over HID on both Windows and Mac OS (Tiger as well as
Leopard), and now want to support Linux as well.
So far I haved tried using libhid and also the lower level USB library. In both
cases I can send data to the device but do not get anything back from device on
the interrupt IN end-point. I can confirm this by looking at the USB protocal
analyser trace. The data sent to the device gets there fine, but the call to
get interrupt data from the device does not work.
I am attaching the pseudo code of using the USB library (libhid gave me similar
results). Do you spot anything wrong in this appraoch?
#define MY_CONTROL_INTERFACE 0x00
#define HID_REPORT_SET 0x09
#define HID_RT_OUTPUT 0x02
main ()
{
struct usb_dev_handle *usb_handle;
int vendorID = 0xAAAA;
int productID = 0xBBBB;
int rv;
// this function gets a list of all USB busses and devices,
// picks up the device corresponding to the given vendor/product IDs
// and returns the handle. I get the correct handle.
usb_handle = MyGetDeviceHandle(vendorID, productID);
// detach kernel driver from my device
rv = usb_detach_kernel_driver_np(usb_handle, MY_CONTROL_INTERFACE);
// claim the interface to this device
rv = usb_claim_interface(usb_handle, MY_CONTROL_INTERFACE);
// prepare data to be sent
int MyReportID = 0;
char *data;
... allocate space for 64 bytes of data, and assign value to it
// send data to device over control end-point
rv = usb_control_msg(usb_handle,
USB_ENDPOINT_OUT + USB_TYPE_CLASS +
USB_RECIP_INTERFACE,
HID_REPORT_SET,
MyReportID + (HID_RT_OUTPUT << 8),
MY_CONTROL_INTERFACE,
data,
64,
3000);
// So far so good, the data is sent correct and I can see it in the device.
char inBuffer[64];
int bytesToRead = 14;
// read response data from device
rv = usb_interrupt_read(usb_handle,
0x04, // end-point to read the interrupt from
inBuffer,
bytesToRead,
3000);
// ERROR: this call fails. I do not see any data on the USB bus.
}
_______________________________________________
libhid-discuss mailing list
[email protected]
http://lists.alioth.debian.org/mailman/listinfo/libhid-discuss
http://libhid.alioth.debian.org/
