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
