3 files changed, 66 insertions, 0 deletions

diff --git a/util/usb_detach/Makefile b/util/usb_detach/Makefile
new file mode 100644
index 000000000..533c1928f
--- /dev/null
+++ b/util/usb_detach/Makefile
@@ -0,0 +1,18 @@
+# the compiler: gcc for C program, define as g++ for C++
+CC = gcc
+
+# compiler flags:
+#  -g    adds debugging information to the executable file
+#  -Wall turns on most, but not all, compiler warnings
+CFLAGS  = -g -Wall
+
+# the build target executable:
+TARGET = usb_detach
+
+all: $(TARGET)
+
+$(TARGET): $(TARGET).c
+        $(CC) $(CFLAGS) -o $(TARGET) $(TARGET).c
+
+clean:
+        $(RM) $(TARGET)
diff --git a/util/usb_detach/readme.md b/util/usb_detach/readme.md
new file mode 100644
index 000000000..ac42944ee
--- /dev/null
+++ b/util/usb_detach/readme.md
@@ -0,0 +1,14 @@
+# usb_detach
+
+When trying to flash on Linux, you may encounter a "Resource Unavailable" error. This means that Linux's HID driver has taken exclusive control of the keyboard, and the program script can't flash it.
+This program can force Linux to give up a device, so that the programming script can reset it.
+
+## To compile:
+```bash
+make clean && make
+```
+
+## To run:
+1. Use `lsusb` to discover the Bus and Device numbers for your keyboard.
+2. Run the program: `sudo ./usb_detach /dev/bus/usb/<BUS>/<DEVICE>`.
+3. Build and program the firmware as normal.
diff --git a/util/usb_detach/usb_detach.c b/util/usb_detach/usb_detach.c
new file mode 100644
index 000000000..786ab5e67
--- /dev/null
+++ b/util/usb_detach/usb_detach.c
@@ -0,0 +1,34 @@
+/* Found at https://www.linuxquestions.org/questions/linux-hardware-18/how-to-unclaim-usb-device-558138/#post3406986 */
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <linux/ioctl.h>
+#include <linux/usbdevice_fs.h>
+
+int main(int argc, char**argv)
+{
+        struct usbdevfs_ioctl command;
+        int ret;
+        int fd;
+        int i;
+        if (argc>1) {
+                fd = open(argv[1],O_RDWR);
+                if (fd<1){
+                        perror("unable to open file");
+                        return 1;
+                }
+                for (i=0;i<255;i++){ // hack: should fetch how many interface there is.
+                        command.ifno = i;
+                        command.ioctl_code = USBDEVFS_DISCONNECT;
+                        command.data = NULL;
+                        ret = ioctl(fd, USBDEVFS_IOCTL, &command);
+                        if(ret!=-1)
+                                printf("un claimed interface %d %d\n",i,ret);
+                }
+        } else {
+                printf ("usage: %s /dev/bus/usb/BUS/DEVICE\n",argv[0]);
+                printf("Release all interfaces of this usb device for usage in virtualisation\n");
+        }
+}
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