If process A has an interface claimed and process B disconnects the
kernel driver then process B can also claim the interface.
I think USBFSDEV_DISCONNECT shouldn't disconnect the usbfs driver.
Something like this (untested) patch. Is this the correct approach or
should userspace processes be more co-operative? e.g., by making
libusb's libusb_kernel_driver_active() returning false if driver ==
"usbfs" and expecting users to only call libusb_detach_kernel_driver()
if one is active.
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1552,7 +1552,8 @@ static int proc_ioctl(struct dev_state *ps, struct
usbdevfs_ioctl *ctl)
/* disconnect kernel driver from interface */
case USBDEVFS_DISCONNECT:
- if (intf->dev.driver) {
+ if (intf->dev.driver
+ && intf->dev.driver != &usbfs_driver.drvwrap.driver) {
driver = to_usb_driver(intf->dev.driver);
dev_dbg(&intf->dev, "disconnect by usbfs\n");
usb_driver_release_interface(driver, intf);
David
--
David Vrabel, Senior Software Engineer, Drivers
CSR, Churchill House, Cambridge Business Park, Tel: +44 (0)1223 692562
Cowley Road, Cambridge, CB4 0WZ http://www.csr.com/
Member of the CSR plc group of companies. CSR plc registered in England and Wales, registered number 4187346, registered office Churchill House, Cambridge Business Park, Cowley Road, Cambridge, CB4 0WZ, United Kingdom
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