Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751473AbaFMOTj (ORCPT ); Fri, 13 Jun 2014 10:19:39 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:34036 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750951AbaFMOTi (ORCPT ); Fri, 13 Jun 2014 10:19:38 -0400 Date: Fri, 13 Jun 2014 10:19:36 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Peter Chen cc: Felipe Balbi , Greg KH , "linux-usb@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: RE: Disable bus's drivers_autoprobe before rootfs has mounted In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 13 Jun 2014, Peter Chen wrote: > OK, we can keep our g_xxx gadget driver just support the basic feature. But > the bug that causes gadget driver load fail due to udc is probed deferral should > be fixed, do you think so, we can't wait until configfs has total been ready. That problem has always existed. There never has been a time when a gadget driver could be loaded before the UDC driver was ready. Does it really need to be fixed now? If you do want to fix the problem, there's a much easier way than what you posted. See below. Alan Stern Index: usb-3.15/include/linux/usb/gadget.h =================================================================== --- usb-3.15.orig/include/linux/usb/gadget.h +++ usb-3.15/include/linux/usb/gadget.h @@ -821,6 +821,7 @@ static inline int usb_gadget_disconnect( * @suspend: Invoked on USB suspend. May be called in_interrupt. * @resume: Invoked on USB resume. May be called in_interrupt. * @driver: Driver model state for this driver. + * @probe_list: List of drivers waiting to be probed. * * Devices are disabled till a gadget driver successfully bind()s, which * means the driver will handle setup() requests needed to enumerate (and @@ -881,6 +882,7 @@ struct usb_gadget_driver { /* FIXME support safe rmmod */ struct device_driver driver; + struct list_head probe_list; }; Index: usb-3.15/drivers/usb/gadget/udc-core.c =================================================================== --- usb-3.15.orig/drivers/usb/gadget/udc-core.c +++ usb-3.15/drivers/usb/gadget/udc-core.c @@ -47,8 +47,12 @@ struct usb_udc { static struct class *udc_class; static LIST_HEAD(udc_list); +static LIST_HEAD(pending_drivers); static DEFINE_MUTEX(udc_lock); +static int udc_bind_to_driver(struct usb_udc *udc, + struct usb_gadget_driver *driver); + /* ------------------------------------------------------------------------- */ #ifdef CONFIG_HAS_DMA @@ -242,6 +246,15 @@ int usb_add_gadget_udc_release(struct de usb_gadget_set_state(gadget, USB_STATE_NOTATTACHED); + while (!list_empty(&pending_drivers)) { + struct usb_gadget_driver *driver; + + driver = list_first_entry(&pending_drivers, + struct usb_gadget_driver, probe_list); + if (udc_bind_to_driver(udc, driver) == 0) + break; + } + mutex_unlock(&udc_lock); return 0; @@ -338,6 +351,7 @@ static int udc_bind_to_driver(struct usb dev_dbg(&udc->dev, "registering UDC driver [%s]\n", driver->function); + list_del_init(&driver->probe_list); udc->driver = driver; udc->dev.driver = &driver->driver; @@ -400,6 +414,7 @@ int usb_gadget_probe_driver(struct usb_g return -EINVAL; mutex_lock(&udc_lock); + INIT_LIST_HEAD(&driver->probe_list); list_for_each_entry(udc, &udc_list, list) { /* For now we take the first one */ if (!udc->driver) @@ -407,8 +422,9 @@ int usb_gadget_probe_driver(struct usb_g } pr_debug("couldn't find an available UDC\n"); + list_add_tail(&driver->probe_list, &pending_drivers); mutex_unlock(&udc_lock); - return -ENODEV; + return 0; found: ret = udc_bind_to_driver(udc, driver); mutex_unlock(&udc_lock); @@ -425,6 +441,7 @@ int usb_gadget_unregister_driver(struct return -EINVAL; mutex_lock(&udc_lock); + list_del(&driver->probe_list); list_for_each_entry(udc, &udc_list, list) if (udc->driver == driver) { usb_gadget_remove_driver(udc); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/