Hello everyone, I recently wanted to pick up again on developing a kernel input driver for the Microsoft Pixelsense (formerly Surface 2.0). I already have a working user space driver (see also [1]). However - just like last year [2] - I quickly ran into an issue with a corrupted device firmware after some brief experimentation with the kernel driver, while the user space driver didn't and doesn't show any such issues. This happened on two separate Pixelsense devices, with different kernel versions. So even though userspace and kernel driver look like they perform exactly the same operations on the device, there must be some difference I don't understand - perhaps libusb does some kind of internal error handling which the kernel doesn't do? Userspace version: // for control commands usb_control_msg(handle, 0xC0, cmd, 0x00, index, (char*)buf, len, 1000); // for bulk data transfer uint8_t buffer[512]; result = usb_bulk_read( handle, 0x86, (char*)(buffer), sizeof(buffer), 1000 ); Kernel version: // for control commands #define surface_command(dev, command, index, buffer, size) usb_control_msg (dev->usbdev, usb_rcvctrlpipe (dev->usbdev, 0), command, USB_TYPE_VENDOR | USB_RECIP_ENDPOINT | USB_DIR_IN, 0x00, index, buffer, size, 1000) // for bulk data transfer result = usb_bulk_msg (surface->usbdev, usb_rcvbulkpipe (surface->usbdev, 0x86), surface->bulk_in_buffer, 512, &bulk_read, 1000); Can anybody venture a guess what kind of functional difference there is between these code snippets? Thanks & BR, Florian [1] https://github.com/floe/surface-2.0/ [2] http://floe.butterbrot.org/matrix/hacking/surface/brick.html -- SENT FROM MY DEC VT50 TERMINAL
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