Linux-USB Archive on lore.kernel.org
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From: Bastien Nocera <hadess@hadess.net>
To: linux-usb@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Benjamin Tissoires <benjamin.tissoires@redhat.com>,
	Bastien Nocera <hadess@hadess.net>,
	Alan Stern <stern@rowland.harvard.edu>
Subject: [PATCH v3 5/6] USB: Fallback to generic driver when specific driver fails
Date: Wed, 16 Oct 2019 11:39:32 +0200
Message-ID: <20191016093933.693-6-hadess@hadess.net> (raw)
In-Reply-To: <20191016093933.693-1-hadess@hadess.net>

If ->probe fails for a device specific driver, ask the driver core to
reprobe us, after having flagged the device for the generic driver to be
forced.

Signed-off-by: Bastien Nocera <hadess@hadess.net>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
---
 drivers/usb/core/driver.c  | 5 ++++-
 drivers/usb/core/generic.c | 3 +++
 include/linux/usb.h        | 1 +
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git drivers/usb/core/driver.c drivers/usb/core/driver.c
index 9d1502a9571d..f81606c6a35b 100644
--- drivers/usb/core/driver.c
+++ drivers/usb/core/driver.c
@@ -270,7 +270,10 @@ static int usb_probe_device(struct device *dev)
 		return error;
 
 	error = udriver->probe(udev);
-	/* TODO: fallback to generic driver in case of error */
+	if (error == -ENODEV && udriver != &usb_generic_driver) {
+		udev->use_generic_driver = 1;
+		return -EPROBE_DEFER;
+	}
 	return error;
 }
 
diff --git drivers/usb/core/generic.c drivers/usb/core/generic.c
index 84da85c13825..4626227a6dd2 100644
--- drivers/usb/core/generic.c
+++ drivers/usb/core/generic.c
@@ -213,6 +213,9 @@ static int __check_usb_generic(struct device_driver *drv, void *data)
 
 static bool usb_generic_driver_match(struct usb_device *udev)
 {
+	if (udev->use_generic_driver)
+		return true;
+
 	/*
 	 * If any other driver wants the device, leave the device to this other
 	 * driver.
diff --git include/linux/usb.h include/linux/usb.h
index 3663bd7b1fa4..ca1a5f1e1c5e 100644
--- include/linux/usb.h
+++ include/linux/usb.h
@@ -708,6 +708,7 @@ struct usb_device {
 	unsigned lpm_disable_count;
 
 	u16 hub_delay;
+	unsigned use_generic_driver:1;
 };
 #define	to_usb_device(d) container_of(d, struct usb_device, dev)
 
-- 
2.21.0


  parent reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-16  9:39 [PATCH v3 0/6] Add Apple MFi fastcharge USB device driver Bastien Nocera
2019-10-16  9:39 ` [PATCH v3 1/6] USB: Export generic USB device driver functions Bastien Nocera
2019-10-16  9:39 ` [PATCH v3 2/6] USB: Make it possible to "subclass" usb_device_driver Bastien Nocera
2019-10-16  9:39 ` [PATCH v3 3/6] USB: Implement usb_device_match_id() Bastien Nocera
2019-10-16  9:39 ` [PATCH v3 4/6] USB: Select better matching USB drivers when available Bastien Nocera
2019-10-16  9:39 ` Bastien Nocera [this message]
2019-10-16  9:39 ` [PATCH v3 6/6] USB: Add driver to control USB fast charge for iOS devices Bastien Nocera
2019-11-21 15:20 ` [PATCH v3 0/6] Add Apple MFi fastcharge USB device driver Bastien Nocera
2020-01-07  8:46   ` Bastien Nocera
2020-01-07  9:35     ` Greg Kroah-Hartman
2020-01-07  9:48       ` Bastien Nocera
2020-02-11  0:21       ` Bastien Nocera
2020-02-12 17:52         ` Greg Kroah-Hartman
2020-02-12 19:06 ` Greg Kroah-Hartman
2020-02-12 23:05   ` Bastien Nocera
2020-02-12 23:17     ` Greg Kroah-Hartman
2020-02-12 23:24       ` Bastien Nocera

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