/[scripts]/trunk/usbreset.c
This is repository of my old source code which isn't updated any more. Go to git.rot13.org for current projects!
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Contents of /trunk/usbreset.c

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Revision 113 - (show annotations)
Fri Apr 10 12:03:35 2009 UTC (14 years, 11 months ago) by dpavlin
File MIME type: text/plain
File size: 1473 byte(s)
reset usb device from userspace

1 /* usbreset -- send a USB port reset to a USB device */
2
3 // http://marc.info/?l=linux-usb-users&m=116827193506484&w=2
4
5 /*
6
7 There is a way to suspend a USB device. In order to use it,
8 you must have a kernel with CONFIG_PM_SYSFS_DEPRECATED turned on. To
9 suspend a device, do (as root):
10
11 echo -n 2 >/sys/bus/usb/devices/.../power/state
12
13 where the "..." is the ID for your device. To unsuspend, do the same
14 thing but with a "0" instead of the "2" above.
15
16 Note that this mechanism is slated to be removed from the kernel within
17 the next year. Hopefully some other mechanism will take its place.
18
19 > To reset a
20 > device?
21
22 Here's a program to do it. You invoke it as either
23
24 usbreset /proc/bus/usb/BBB/DDD
25 or
26 usbreset /dev/usbB.D
27
28 depending on how your system is set up, where BBB and DDD are the bus and
29 device address numbers.
30
31 Alan Stern
32
33 */
34
35 #include <stdio.h>
36 #include <unistd.h>
37 #include <fcntl.h>
38 #include <errno.h>
39 #include <sys/ioctl.h>
40
41 #include <linux/usbdevice_fs.h>
42
43
44 int main(int argc, char **argv)
45 {
46 const char *filename;
47 int fd;
48 int rc;
49
50 if (argc != 2) {
51 fprintf(stderr, "Usage: usbreset device-filename\n");
52 return 1;
53 }
54 filename = argv[1];
55
56 fd = open(filename, O_WRONLY);
57 if (fd < 0) {
58 perror("Error opening output file");
59 return 1;
60 }
61
62 printf("Resetting USB device %s\n", filename);
63 rc = ioctl(fd, USBDEVFS_RESET, 0);
64 if (rc < 0) {
65 perror("Error in ioctl");
66 return 1;
67 }
68 printf("Reset successful\n");
69
70 close(fd);
71 return 0;
72 }

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