Hi Alan, Thanks for the response. I have not read hiddev.txt, so that explains the incorrect expectations. If I may ask, why is the value a 4-byte field? Is that just to round it to 8 bytes? The "English" version of the descriptor is as follows, from the original LUFA source: HID_DESCRIPTOR_VENDOR(0x00, 0x01, 0x02, 0x03, GENERIC_REPORT_SIZE) /* GENERIC_REPORT_SIZE == 64 */ And parsed using http://eleccelerator.com/usbdescreqparser/, translates to: 0x06, 0x00, 0xFF, // Usage Page (Vendor Defined 0xFF00) 0x09, 0x01, // Usage (0x01) 0xA1, 0x01, // Collection (Application) 0x09, 0x02, // Usage (0x02) 0x15, 0x00, // Logical Minimum (0) 0x25, 0xFF, // Logical Maximum (255) 0x75, 0x08, // Report Size (8) 0x95, 0x40, // Report Count (64) 0x81, 0x02, // Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position) 0x09, 0x03, // Usage (0x03) 0x15, 0x00, // Logical Minimum (0) 0x25, 0xFF, // Logical Maximum (255) 0x75, 0x08, // Report Size (8) 0x95, 0x40, // Report Count (64) 0x91, 0x02, // Output (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position,Non-volatile) 0xC0, // End Collection // 32 bytes So I apparently need to extract just the 5th byte from the packet, and discard the rest. Excellent! Thank you! Rogan On Sat, Jan 7, 2017 at 7:12 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Sat, 7 Jan 2017, Rogan Dawes wrote: > >> Hi folks, >> >> I'm trying to port the USaBUSe project >> (https://github.com/SensePost/USaBUSe) from an AVR microcontroller to >> the Linux USB gadget stack. USaBUSe implements a combined keyboard and >> mouse via a single HID endpoint, as well as a raw HID endpoint, which >> is used as a bi-directional comms channel. >> >> I have managed to get the combined keyboard and mouse working, by >> extending the report size to 9 instead of 8, and writing the report ID >> as the first byte of the report to /dev/hidg0. And the performance is >> excellent, 300 characters per second with no problems! Thank you! >> >> However, I'm now trying to figure out how to use the raw hid interface >> as a "pipe". I ran the following on a Linux host, to which my gadget >> was connected: >> >> rogan:/dev/usb# cat hiddev0 | hexdump -C >> >> In order to see what the host received when I sent data to /dev/hidg1 >> on the gadget host. >> >> $ echo "foo" > /dev/hidg1 >> 00000000 02 00 00 ff 66 00 00 00 02 00 00 ff 6f 00 00 00 |....f.......o...| >> 00000010 02 00 00 ff 6f 00 00 00 02 00 00 ff 0a 00 00 00 |....o...........| >> 00000020 02 00 00 ff 00 00 00 00 02 00 00 ff 00 00 00 00 |................| >> * >> >> $ echo "bar" > /dev/hidg1 >> 00000200 02 00 00 ff 62 00 00 00 02 00 00 ff 61 00 00 00 |....b.......a...| >> 00000210 02 00 00 ff 72 00 00 00 02 00 00 ff 0a 00 00 00 |....r...........| >> 00000220 02 00 00 ff 00 00 00 00 02 00 00 ff 00 00 00 00 |................| >> * >> $ printf "1234567890 < to fill a 64 byte packet" > /dev/hidg1 >> 00000400 02 00 00 ff 31 00 00 00 02 00 00 ff 32 00 00 00 |....1.......2...| >> 00000410 02 00 00 ff 33 00 00 00 02 00 00 ff 34 00 00 00 |....3.......4...| >> 00000420 02 00 00 ff 35 00 00 00 02 00 00 ff 36 00 00 00 |....5.......6...| >> 00000430 02 00 00 ff 37 00 00 00 02 00 00 ff 38 00 00 00 |....7.......8...| >> 00000440 02 00 00 ff 39 00 00 00 02 00 00 ff 30 00 00 00 |....9.......0...| > ... > >> Which is somewhat surprising! > > Have you read Documentation/hid/hiddev.txt? This looks basically > right: Each character gives rise to an 8-byte event, where the first 4 > bytes contain the HID usage page and code, and the second 4 bytes > contain the updated value. To get the original data as written to the > hidg1 file, just extract the fifth byte from each group of 8. > >> Can anyone tell me what I am doing wrong? > > Probably nothing, other than having wrong expectations. > >> Here is the setup script that I am using: >> >> #!/bin/bash >> >> # based on hidonly.sh by >> # >> # Collin Mulliner <collin AT mulliner.org> >> # >> >> # Check if the hardware has USB Device Controller capabilty >> UDC=`ls /sys/class/udc/` >> if [ -z "$UDC" ] ; then >> echo "No USB Device Controller hardware found, cannot continue!" >> exit 1 >> fi >> >> modprobe -r g_ether usb_f_ecm usb_f_rndis u_ether >> modprobe usb_f_hid >> >> cd /sys/kernel/config/ >> # Create a gadget >> mkdir usb_gadget/g1 >> cd usb_gadget/g1 >> >> # define basic device properties, and corresponding strings >> echo 0x1209 > idVendor >> echo 0x6667 > idProduct >> echo 0x0100 > bcdDevice # v1.0.0 >> echo 0x0200 > bcdUSB # USB2 >> >> # 0x0409 is English (United States) >> mkdir strings/0x409 >> # echo "fedcba9876543210" > strings/0x409/serialnumber >> echo "SensePost" > strings/0x409/manufacturer >> echo "USaBUSe" > strings/0x409/product >> >> # define how many configurations the device has. Most will just have one >> mkdir configs/c.1 >> # define Max power consumption for Config 1 >> echo 120 > configs/c.1/MaxPower >> >> # define Strings related to Config 1 >> mkdir configs/c.1/strings/0x409 >> echo "Default" > configs/c.1/strings/0x409/configuration >> >> # define the available functions that the device supports >> >> # Set up the combined keyboard and mouse >> mkdir functions/hid.usb0 >> cd functions/hid.usb0 >> # Non-boot protocol == 0, Keyboard Boot Protocol == 1, Mouse Boot Protocol == 2 >> echo 0 > protocol >> # Non-boot subclass == 0, Boot subclass == 1 >> echo 0 > subclass >> >> # Report length is 9 rather than 8, because we include the report >> identifier before the keyboard report >> # This must correspond closely with the report descriptor that follows >> echo 9 > report_length >> echo -ne "\x05\x01\x09\x02\xA1\x01\x85\x01\x09\x01\xA1\x00\x05\x09\x19\x01\x29\x03\x15\x00\x25\x01\x95\x03\x75\x01\x81\x02\x95\x01\x75\x05\x81\x01\x05\x01\x09\x30\x09\x31\x15\x81\x25\x7F\x35\x81\x45\x7F\x95\x02\x75\x08\x81\x06\xC0\xC0\x05\x01\x09\x06\xA1\x01\x85\x02\x05\x07\x19\xE0\x29\xE7\x15\x00\x25\x01\x75\x01\x95\x08\x81\x02\x95\x01\x75\x08\x81\x01\x05\x08\x19\x01\x29\x05\x95\x05\x75\x01\x91\x02\x95\x01\x75\x03\x91\x01\x15\x00\x25\x65\x05\x07\x19\x00\x29\x65\x95\x06\x75\x08\x81\x00\xC0" >> > report_desc >> cd ../.. >> >> # Set up the raw HID interface >> mkdir functions/hid.usb1 >> cd functions/hid.usb1 >> # Non-boot protocol == 0, Keyboard Boot Protocol == 1, Mouse Boot Protocol == 2 >> echo 0 > protocol >> # Non-boot subclass == 0, Boot subclass == 1 >> echo 0 > subclass >> >> # Report length is 9 rather than 8, because we include the report >> identifier before the keyboard report >> # This must correspond closely with the report descriptor that follows >> echo 64 > report_length >> echo -ne "\x06\x00\xFF\x09\x01\xA1\x01\x09\x02\x15\x00\x25\xFF\x75\x08\x95\x40\x81\x02\x09\x03\x15\x00\x25\xFF\x75\x08\x95\x40\x91\x02\xC0" >> > report_desc > > Would you care to provide an English version of this report descriptor? > I'm not so good at reading hex and mentally performing the rather > arcane translation into the descriptor language. > >> cd ../.. >> >> # make the functions available in the defined configuration >> ln -s functions/hid.usb0 configs/c.1 >> ln -s functions/hid.usb1 configs/c.1 >> >> # enable the device >> echo "$UDC" > UDC > > Alan Stern > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
