Hi Shuah,
For me, I want to let the remote control software passing some virtual
device (e.g. ethernet device) to the remote computer.
More specifically, the remote computer is connected to a private
network, and the local computer is connected to the Internet. And the
local can only connect to the remote computer using RDP/SPICE protocols,
some other softwares such as vmware client, or even remote management cards.
All these protocols or softwares support USB redirection. So I can
create a virtual ethernet device with usbip, let them redirect the USB
ethernet device to the remote computer, and enable NAT forward.
Then I am able to access the private network with local computer.
Currently, I am writing a user-space program. It runs usbip protocol,
and can be connected and attached to the vhci.
But the USB redirection will always reset the USB device before it
passing the device to the remote computer.
And now, this "reset" results the device be disabled and never be
enabled again. So the redirection fails.
In addition to this, I think usbip is a great module to allow the user
emulate some other devices and passing them to the remote computer
easily. For example, the virtual serial port can be emulated in
user-space, and communicate with the remote computer over SPICE. And
then, I can get the console output from the remote computer or send
console command to it.
Thanks,
Zhai Zhaoxuan
On 12/12/19 12:00 AM, Shuah Khan wrote:
On 12/10/19 4:43 AM, Zhai Zhaoxuan wrote:
Hi,
I am trying to implement a virtual USB device using usbip. But I get
a trouble.
Can you give me more details on why you are planning to add virtual USB
to usbip? How does it work with conjunction with the usbip server side?
When a running port on vhci_hcd is resetted (by setting
USB_PORT_FEAT_RESET), it will never be enabled again.
The kernel version is 5.5.0-rc1-00012-g6794862a16ef.
In the source file drivers/usb/usbip/vhci_hcd.c:
565 case USB_PORT_FEAT_RESET:
...
572 /* if it's already enabled, disable */
573 if (hcd->speed == HCD_USB3) {
574 vhci_hcd->port_status[rhport] = 0;
575 vhci_hcd->port_status[rhport] =
576 (USB_SS_PORT_STAT_POWER |
577 USB_PORT_STAT_CONNECTION |
578 USB_PORT_STAT_RESET);
579 } else if (vhci_hcd->port_status[rhport] &
USB_PORT_STAT_ENABLE) {
580 vhci_hcd->port_status[rhport] &=
~(USB_PORT_STAT_ENABLE
581 | USB_PORT_STAT_LOW_SPEED
582 | USB_PORT_STAT_HIGH_SPEED);
583 }
584
The USB_PORT_STAT_ENABLE is cleard. And it should be set later.
But, the GetPortStatus only set the USB_PORT_STAT_ENABLE for
not-assigned ports.
430 case GetPortStatus:
...
456 if (vhci_hcd->vdev[rhport].ud.status ==
457 VDEV_ST_NOTASSIGNED) {
458 usbip_dbg_vhci_rh(
459 " enable rhport %d (status %u)\n",
460 rhport,
461 vhci_hcd->vdev[rhport].ud.status);
462 vhci_hcd->port_status[rhport] |=
463 USB_PORT_STAT_ENABLE;
464 }
The used port (status == VDEV_ST_USED) will be disabled after
USB_PORT_FEAT_RESET, and unable to be enabled again.
Should VDEV_ST_USED be added to line 457?
And if it shouldn't, how can I enable a port after USB_PORT_FEAT_RESET?
I would like to see server and client side patches and a use-case for
adding virtual device.
thanks,
-- Shuah
