On Thu, 10 Dec 2009, Pratik Prajapati wrote: > Hi there, > > > I'm facing an issue with patch of "debounce before unregistering" > > rerefence: > http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.27.y.git;a=commit;h=24618b0cd42f936cda461bdf6144670a5c925178 > > > When I'm connecting USB pen drive, it doesn't get detected on my > board. kernel linux-2.6.28 gives error "unable to enumerate USB device > on port 1" > > But on linux-2.6.25 (on the same board) it works fine. > > To debug further I have traced this error message. > > > With linux-2.6.25 kernel, > > file: driver/usb/core/hub.c > function: hub_port_connect_change > has portchange &= ~USB_PORT_STAT_C_CONNECTION; > > But in linux-2.6.28 kernel patch of "debounce before unregistering" is > present. Which masks USB_PORT_STAT_C_CONNECTION as well as > USB_PORT_STAT_C_ENABLE. Are you talking about this code? #ifdef CONFIG_USB_OTG /* during HNP, don't repeat the debounce */ if (hdev->bus->is_b_host) portchange &= ~(USB_PORT_STAT_C_CONNECTION | USB_PORT_STAT_C_ENABLE); #endif > To experiment, I have changed the code to portchange &= > ~USB_PORT_STAT_C_CONNECTION ( removed masking of > USB_PORT_STAT_C_ENABLE) in linux-2.6.28. And my USB pen drive got > detected with linux-2.6.28 also. > > > Now I don't understand logic behind masking USB_PORT_STAT_C_ENABLE in > portchange. > > Kindly explain me what could be the issue? That code should not affect you at all, since it runs only when your controller is a B-host and that can never happen when you plug in a USB pendrive. If it _does_ affect you then because your controller driver must be doing something wrong (setting bus->is_b_host even when the controller is an A-host). Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
