bash C - 如何在 Linux 下重置 USB 总线？
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C - how can i reset the USB Bus under linux?
提问by
Daily--about 5 to 10 times--my USB camera disappears from the system. It's been happening from day 1 because the manufacturer driver is not compatible with Linux. lsusband dmesgshow it correctly at first, but after a longer period of time sometimes it disappears. The best solution to fix it is to reset the USB interface for that camera to get it back. I did it a few times manually using the C source code and it worked, but when I am doing it in a Bash loop it seems it's failing over and over. Any idea?
每天——大约 5 到 10 次——我的 USB 摄像头从系统中消失。它从第一天开始就发生了，因为制造商驱动程序与 Linux 不兼容。lsusb并且一dmesg开始正确显示，但经过较长时间后有时会消失。修复它的最佳解决方案是重置该相机的 USB 接口以将其恢复。我使用 C 源代码手动做了几次并且它工作了，但是当我在 Bash 循环中做它时，它似乎一遍又一遍地失败。任何的想法？
How can I make both programs work, so that I get my /dev/video0or 1or 2always available?
我怎样才能让这两个程序的工作，让我得到我的 /dev/video0或者1或2始终可用？
Step 1:Resetting the USB bus under Linux using this code:
步骤 1：使用以下代码在 Linux 下重置 USB 总线：
/* few times it's resetting but when I use it in a Bash loop it's not doing it */
#include <stdio.h>
#include <usb.h>
int main(int argc, char *argv[]) {
struct usb_bus *busses;
usb_init();
usb_find_busses();
usb_find_devices();
busses = usb_get_busses();
struct usb_bus *bus;
int c, i, a;
for (bus = busses; bus; bus = bus->next) {
struct usb_device *dev;
int val;
usb_dev_handle *junk;
for (dev = bus->devices; dev; dev = dev->next) {
char buf[1024];
junk = usb_open ( dev );
usb_get_string_simple(junk,2,buf,1023);
switch(argc) {
case 1:
if ( junk == NULL ) {
printf("Can't open %p (%s)\n", dev, buf );
} else if (strcmp(buf,"HD Pro Webcam C920")==0) {
val = usb_reset(junk);
printf( "reset %p %d (%s)\n", dev, val, buf );
}
break;
default:
if ( junk == NULL ){
printf("Can't open %p (%s)\n", dev, buf );
} else {
val = usb_reset(junk);
printf( "reset %p %d (%s)\n", dev, val, buf );
}
}
usb_close(junk);
}
}
}
Step 2:Running as scanner - to make sure video0 or 1 or 2 is available, if not available resetting the USB bus
第 2 步：作为扫描仪运行 - 确保 video0 或 1 或 2 可用，如果不可用则重置 USB 总线
#!/bin/bash
j=true
while $j
do
for i in 0 1 2
do
tmp="/dev/video$i"
if [ -e $tmp ]
then
echo "/dev/video$i"
j=false
else
echo "NO - camera found - restarting the USB $i"
echo ROOT_PASSWORD_TO_EXECUTE | sudo -S /var/tmp/c-restartusb/restartusb
fi
done
done
echo "Camera - logic ended, expecting the camera is available now"
Step 3:Still it's not available?
第 3 步：仍然不可用？
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
NO - camera found - restart the USB 2
NO - camera found - restart the USB 0
NO - camera found - restart the USB 1
回答by Jiejing Zhang
Don't sure your reset usb code right...
不确定您的重置 USB 代码是否正确...
Can you find the usb device ?
你能找到USB设备吗？
If you can, try below:
如果可以，请尝试以下操作：
BTW, This code is from here. should be work if you can find the usb node:
顺便说一句，此代码来自此处。如果你能找到 USB 节点，应该可以工作：
/* usbreset -- send a USB port reset to a USB device */
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <linux/usbdevice_fs.h>
int main(int argc, char **argv)
{
const char *filename;
int fd;
int rc;
if (argc != 2) {
fprintf(stderr, "Usage: usbreset device-filename\n");
return 1;
}
filename = argv[1];
fd = open(filename, O_WRONLY);
if (fd < 0) {
perror("Error opening output file");
return 1;
}
printf("Resetting USB device %s\n", filename);
rc = ioctl(fd, USBDEVFS_RESET, 0);
if (rc < 0) {
perror("Error in ioctl");
return 1;
}
printf("Reset successful\n");
close(fd);
return 0;
}
If you can't, you maybe want to rescan to find the usb device like this:
如果你不能，你可能想重新扫描以找到这样的 USB 设备：
echo 1 > /sys/dev/block/8:16/device/rescan
