On Sat, 17 Apr 2010, Jan-Patrick Bolte wrote:
>
> >> Dear Mister Stern,
> >>
> >> I want to turn off the power at one of my USB-Ports (Port_#0002.Hub_#0003).
> >> I read your articles at http://www.kernel.org/ and hope you can help me
> >> by writing a Batch for turning off the USB-Power.
> >>
> >
> > Are you aware that most USB hubs are not able to turn off power to
> > their ports?
> >
> Sure, many hubs aren't able to turn off power but I hope my one is able
> to do.
Okay. Attached is the source code for a program named hubpower. You
can use it to tell your hubs to turn their port power on and off.
To compile the program, all you have to do is:
gcc -o hubpower hubpower.c
You'll probably need to run it with sudo. Tell the program the hub's
bus number and device number, and give it a list of ports and power
settings. For example,
sudo ./hubpower 1:3 power 4 on 2 off
This will tell hub 3 on bus 1 to turn port 4's power on and port 2's
power off. Because of the way the Linux USB stack works, the program
will also unbind the hub from the kernel driver when you do this, so
the system will think that all devices attached to the hub have been
unplugged.
You can tell the system to bind the hub back to the kernel driver.
The devices plugged into the hub won't work again until you do this:
sudo ./hubpower 1:3 bind
However when you do this, the kernel driver will turn power for all the
ports back on. There is no way to tell the Linux hub driver to leave a
port powered off.
Finally, you can see the current status of every port by doing:
sudo ./hubpower 1:3 status
Alan Stern
/* hubpower -- control the power settings for a USB hub
*
* To build: gcc -o hubpower hubpower.c
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <asm/byteorder.h>
#include <linux/usbdevice_fs.h>
#include <linux/usb/ch9.h>
#define USB_HUB_TIMEOUT 5000 /* milliseconds */
#define USB_PORT_FEAT_POWER 8
#define USB_DT_HUB (USB_TYPE_CLASS | 0x09)
#define USB_DT_HUB_SIZE 7
struct usb_hub_descriptor {
__u8 bDescLength;
__u8 bDescriptorType;
__u8 bNbrPorts;
__le16 wHubCharacteristics;
__u8 bPwrOn2PwrGood;
__u8 bHubContrCurrent;
} __attribute__ ((packed));
struct usb_port_status {
__le16 wPortStatus;
__le16 wPortChange;
} __attribute__ ((packed));
#define USB_PORT_STAT_CONNECTION 0x0001
#define USB_PORT_STAT_ENABLE 0x0002
#define USB_PORT_STAT_SUSPEND 0x0004
#define USB_PORT_STAT_OVERCURRENT 0x0008
#define USB_PORT_STAT_RESET 0x0010
#define USB_PORT_STAT_L1 0x0020
/* bits 6 to 7 are reserved */
#define USB_PORT_STAT_POWER 0x0100
#define USB_PORT_STAT_LOW_SPEED 0x0200
#define USB_PORT_STAT_HIGH_SPEED 0x0400
#define USB_PORT_STAT_TEST 0x0800
#define USB_PORT_STAT_INDICATOR 0x1000
#define USB_PORT_STAT_POWER_3 0x0200 /* USB 3.0 */
int fd; /* Hub device file */
int usb_level;
void usage(void)
{
fprintf(stderr, "Usage:"
"\thubpower busnum:devnum power {portnum (on|off)} ...\n"
"\thubpower busnum:devnum status\n"
"\thubpower busnum:devnum bind\n"
);
exit(1);
}
void port_status(int portnum)
{
struct usbdevfs_ctrltransfer ctrl;
struct usb_port_status pstat;
int rc;
ctrl.bRequestType = USB_DIR_IN | USB_TYPE_CLASS |
USB_RECIP_OTHER;
ctrl.bRequest = USB_REQ_GET_STATUS;
ctrl.wValue = 0;
ctrl.wIndex = portnum;
ctrl.wLength = sizeof(pstat);
ctrl.timeout = USB_HUB_TIMEOUT;
ctrl.data = &pstat;
rc = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
if (rc == -1) {
fprintf(stderr, "Error in ioctl "
"(get port %d status): %s\n",
portnum, strerror(errno));
return;
}
printf("Port %2d status: %04x ", portnum, pstat.wPortStatus);
if (usb_level <= 2) {
if (pstat.wPortStatus & USB_PORT_STAT_INDICATOR)
printf(" Indicator");
if (pstat.wPortStatus & USB_PORT_STAT_TEST)
printf(" Test-Mode");
if (pstat.wPortStatus & USB_PORT_STAT_HIGH_SPEED)
printf(" High-Speed");
if (pstat.wPortStatus & USB_PORT_STAT_LOW_SPEED)
printf(" Low-Speed");
if (pstat.wPortStatus & USB_PORT_STAT_POWER)
printf(" Power-On");
else
printf(" Power-Off");
} else if (usb_level == 3) {
if (pstat.wPortStatus & USB_PORT_STAT_POWER_3)
printf(" Power-On");
else
printf(" Power-Off");
}
if (pstat.wPortStatus & USB_PORT_STAT_RESET)
printf(" Resetting");
if (pstat.wPortStatus & USB_PORT_STAT_OVERCURRENT)
printf(" Overcurrent");
if (pstat.wPortStatus & USB_PORT_STAT_SUSPEND)
printf(" Suspended");
if (pstat.wPortStatus & USB_PORT_STAT_ENABLE)
printf(" Enabled");
if (pstat.wPortStatus & USB_PORT_STAT_CONNECTION)
printf(" Connected");
printf("\n");
}
int main(int argc, char **argv)
{
int busnum, devnum, numports;
enum {DO_POWER, DO_STATUS, DO_BIND} action;
char fname1[40], fname2[40];
int rc;
int portnum;
struct usb_device_descriptor dev_descr;
struct usb_hub_descriptor hub_descr;
struct usbdevfs_ctrltransfer ctrl;
struct usbdevfs_ioctl usb_ioctl;
int bus_endian;
if (argc < 3)
usage();
if (sscanf(argv[1], "%d:%d", &busnum, &devnum) != 2 ||
busnum <= 0 || busnum > 255 ||
devnum <= 0 || devnum > 255)
usage();
if (strcmp(argv[2], "power") == 0) {
action = DO_POWER;
if ((argc - 3) % 2 != 0)
usage();
} else if (strcmp(argv[2], "status") == 0) {
action = DO_STATUS;
if (argc != 3)
usage();
} else if (strcmp(argv[2], "bind") == 0) {
action = DO_BIND;
if (argc != 3)
usage();
} else {
usage();
}
sprintf(fname1, "/dev/bus/usb/%03d/%03d", busnum, devnum);
sprintf(fname2, "/proc/bus/usb/%03d/%03d", busnum, devnum);
bus_endian = 1;
fd = open(fname1, O_RDWR);
if (fd < 0) {
int err1 = errno;
bus_endian = 0;
fd = open(fname2, O_RDWR);
if (fd < 0) {
fprintf(stderr, "Unable to open device file %s: %s\n",
fname1, strerror(err1));
fprintf(stderr, "Unable to open device file %s: %s\n",
fname2, strerror(errno));
return 1;
}
}
rc = read(fd, &dev_descr, USB_DT_DEVICE_SIZE);
if (rc != USB_DT_DEVICE_SIZE) {
perror("Error reading device descriptor");
return 1;
}
if (dev_descr.bDeviceClass != USB_CLASS_HUB) {
fprintf(stderr, "Device %d:%d is not a hub\n",
busnum, devnum);
return 1;
}
if (bus_endian) {
dev_descr.bcdUSB = __le16_to_cpu(dev_descr.bcdUSB);
}
usb_level = dev_descr.bcdUSB >> 8;
ctrl.bRequestType = USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_DEVICE;
ctrl.bRequest = USB_REQ_GET_DESCRIPTOR;
ctrl.wValue = USB_DT_HUB << 8;
ctrl.wIndex = 0;
ctrl.wLength = USB_DT_HUB_SIZE;
ctrl.timeout = USB_HUB_TIMEOUT;
ctrl.data = &hub_descr;
rc = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
if (rc == -1) {
perror("Error in ioctl (read hub descriptor)");
return 1;
}
numports = hub_descr.bNbrPorts;
if (action == DO_STATUS) {
for (portnum = 1; portnum <= numports; ++portnum)
port_status(portnum);
return 0;
}
if (action == DO_BIND) {
usb_ioctl.ifno = 0;
usb_ioctl.ioctl_code = USBDEVFS_CONNECT;
usb_ioctl.data = NULL;
rc = ioctl(fd, USBDEVFS_IOCTL, &usb_ioctl);
if (rc == -1) {
perror("Error in ioctl (USBDEVFS_CONNECT)");
return 1;
}
printf("Bind-driver request sent to the kernel\n");
return 0;
}
if (action == DO_POWER) {
int i;
usb_ioctl.ifno = 0;
usb_ioctl.ioctl_code = USBDEVFS_DISCONNECT;
usb_ioctl.data = NULL;
rc = ioctl(fd, USBDEVFS_IOCTL, &usb_ioctl);
if (rc == -1 && errno != ENODATA) {
perror("Error in ioctl (USBDEVFS_DISCONNECT)");
return 1;
}
for (i = 3; i < argc; i += 2) {
portnum = atoi(argv[i]);
if (portnum < 1 || portnum > numports) {
fprintf(stderr, "Invalid port number: %d\n",
portnum);
continue;
}
if (strcmp(argv[i+1], "on") == 0)
ctrl.bRequest = USB_REQ_SET_FEATURE;
else if (strcmp(argv[i+1], "off") == 0)
ctrl.bRequest = USB_REQ_CLEAR_FEATURE;
else {
fprintf(stderr, "Invalid port power level: %s\n)",
argv[i+1]);
continue;
}
ctrl.bRequestType = USB_DIR_OUT | USB_TYPE_CLASS |
USB_RECIP_OTHER;
ctrl.wValue = USB_PORT_FEAT_POWER;
ctrl.wIndex = portnum;
ctrl.wLength = 0;
ctrl.timeout = USB_HUB_TIMEOUT;
ctrl.data = NULL;
rc = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
if (rc == -1) {
fprintf(stderr, "Error in ioctl "
"(set/clear port %d feature): %s\n",
portnum, strerror(errno));
continue;
}
port_status(portnum);
}
}
return 0;
}
