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dpavlin |
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/* usbreset -- send a USB port reset to a USB device */ |
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/* |
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dpavlin |
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http://marc.info/?l=linux-usb-users&m=116827193506484&w=2 |
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and needs mounted usbfs filesystem |
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sudo mount -t usbfs none /proc/bus/usb |
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dpavlin |
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There is a way to suspend a USB device. In order to use it, |
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you must have a kernel with CONFIG_PM_SYSFS_DEPRECATED turned on. To |
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suspend a device, do (as root): |
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echo -n 2 >/sys/bus/usb/devices/.../power/state |
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where the "..." is the ID for your device. To unsuspend, do the same |
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thing but with a "0" instead of the "2" above. |
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Note that this mechanism is slated to be removed from the kernel within |
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the next year. Hopefully some other mechanism will take its place. |
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> To reset a |
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> device? |
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Here's a program to do it. You invoke it as either |
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usbreset /proc/bus/usb/BBB/DDD |
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or |
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usbreset /dev/usbB.D |
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depending on how your system is set up, where BBB and DDD are the bus and |
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device address numbers. |
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Alan Stern |
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*/ |
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#include <stdio.h> |
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#include <unistd.h> |
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#include <fcntl.h> |
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#include <errno.h> |
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#include <sys/ioctl.h> |
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#include <linux/usbdevice_fs.h> |
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int main(int argc, char **argv) |
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{ |
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const char *filename; |
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int fd; |
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int rc; |
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if (argc != 2) { |
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fprintf(stderr, "Usage: usbreset device-filename\n"); |
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return 1; |
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} |
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filename = argv[1]; |
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fd = open(filename, O_WRONLY); |
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if (fd < 0) { |
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perror("Error opening output file"); |
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return 1; |
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} |
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printf("Resetting USB device %s\n", filename); |
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rc = ioctl(fd, USBDEVFS_RESET, 0); |
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if (rc < 0) { |
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perror("Error in ioctl"); |
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return 1; |
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} |
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printf("Reset successful\n"); |
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close(fd); |
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return 0; |
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} |