USB: add a blacklist for devices that can't handle some things we throw at them.

This adds a blacklist to the USB core to handle some autosuspend and
string issues that devices have.

Originally written by Oliver, but hacked up a lot by Greg.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/Makefile

@@ -4,7 +4,7 @@
 
 usbcore-objs	:= usb.o hub.o hcd.o urb.o message.o driver.o \
 			config.o file.o buffer.o sysfs.o endpoint.o \
-			devio.o notify.o generic.o
+			devio.o notify.o generic.o quirks.o
 
 ifeq ($(CONFIG_PCI),y)
 	usbcore-objs	+= hcd-pci.o

drivers/usb/core/hub.c

@@ -1287,6 +1287,9 @@ int usb_new_device(struct usb_device *udev)
 	if (!try_module_get(THIS_MODULE))
 		return -EINVAL;
 
+	/* Determine quirks */
+	usb_detect_quirks(udev);
+
 	err = usb_get_configuration(udev);
 	if (err < 0) {
 		dev_err(&udev->dev, "can't read configurations, error %d\n",

drivers/usb/core/message.c

@@ -11,6 +11,7 @@
 #include <linux/timer.h>
 #include <linux/ctype.h>
 #include <linux/device.h>
+#include <linux/usb/quirks.h>
 #include <asm/byteorder.h>
 #include <asm/scatterlist.h>
 
@@ -685,6 +686,9 @@ static int usb_string_sub(struct usb_device *dev, unsigned int langid,
 
 	/* Try to read the string descriptor by asking for the maximum
 	 * possible number of bytes */
+	if (dev->quirks & USB_QUIRK_STRING_FETCH_255)
+		rc = -EIO;
+	else
 		rc = usb_get_string(dev, langid, index, buf, 255);
 
 	/* If that failed try to read the descriptor length, then

drivers/usb/core/quirks.c

+/*
+ * USB device quirk handling logic and table
+ *
+ * Copyright (c) 2007 Oliver Neukum
+ * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation, version 2.
+ *
+ *
+ */
+
+#include <linux/usb.h>
+#include <linux/usb/quirks.h>
+#include "usb.h"
+
+/* List of quirky USB devices.  Please keep this list ordered by:
+ * 	1) Vendor ID
+ * 	2) Product ID
+ * 	3) Class ID
+ *
+ * as we want specific devices to be overridden first, and only after that, any
+ * class specific quirks.
+ *
+ * Right now the logic aborts if it finds a valid device in the table, we might
+ * want to change that in the future if it turns out that a whole class of
+ * devices is broken...
+ */
+static const struct usb_device_id usb_quirk_list[] = {
+	/* HP 5300/5370C scanner */
+	{ USB_DEVICE(0x03f0, 0x0701), .driver_info = USB_QUIRK_STRING_FETCH_255 },
+
+	/* Elsa MicroLink 56k (V.250) */
+	{ USB_DEVICE(0x05cc, 0x2267), .driver_info = USB_QUIRK_NO_AUTOSUSPEND },
+
+	{ }  /* terminating entry must be last */
+};
+
+static void usb_autosuspend_quirk(struct usb_device *udev)
+{
+	/* unbalanced resume to prevent autosuspends */
+	usb_autoresume_device(udev);
+}
+
+static const struct usb_device_id *find_id(struct usb_device *udev)
+{
+	const struct usb_device_id *id = usb_quirk_list;
+
+	for (; id->idVendor || id->bDeviceClass || id->bInterfaceClass ||
+			id->driver_info; id++) {
+		if (usb_match_device(udev, id))
+			return id;
+	}
+	return NULL;
+}
+
+/*
+ * Detect any quirks the device has, and do any housekeeping for it if needed.
+ */
+void usb_detect_quirks(struct usb_device *udev)
+{
+	const struct usb_device_id *id = usb_quirk_list;
+
+	id = find_id(udev);
+	if (id)
+		udev->quirks = (u32)(id->driver_info);
+	if (udev->quirks)
+		dev_dbg(&udev->dev, "USB quirks for this device: %x\n",
+				udev->quirks);
+
+	/* do any special quirk handling here if needed */
+	if (udev->quirks & USB_QUIRK_NO_AUTOSUSPEND)
+		usb_autosuspend_quirk(udev);
+}

drivers/usb/core/sysfs.c

@@ -148,6 +148,16 @@ show_maxchild(struct device *dev, struct device_attribute *attr, char *buf)
 }
 static DEVICE_ATTR(maxchild, S_IRUGO, show_maxchild, NULL);
 
+static ssize_t
+show_quirks(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct usb_device *udev;
+
+	udev = to_usb_device(dev);
+	return sprintf(buf, "0x%x\n", udev->quirks);
+}
+static DEVICE_ATTR(quirks, S_IRUGO, show_quirks, NULL);
+
 /* Descriptor fields */
 #define usb_descriptor_attr_le16(field, format_string)			\
 static ssize_t								\
@@ -204,6 +214,7 @@ static struct attribute *dev_attrs[] = {
 	&dev_attr_devnum.attr,
 	&dev_attr_version.attr,
 	&dev_attr_maxchild.attr,
+	&dev_attr_quirks.attr,
 	NULL,
 };
 static struct attribute_group dev_attr_grp = {

drivers/usb/core/usb.h

@@ -13,6 +13,7 @@ extern void usb_disable_interface (struct usb_device *dev,
 		struct usb_interface *intf);
 extern void usb_release_interface_cache(struct kref *ref);
 extern void usb_disable_device (struct usb_device *dev, int skip_ep0);
+extern void usb_detect_quirks(struct usb_device *udev);
 
 extern int usb_get_device_descriptor(struct usb_device *dev,
 		unsigned int size);

include/linux/usb.h

@@ -388,6 +388,7 @@ struct usb_device {
 	struct usb_device *children[USB_MAXCHILDREN];
 
 	int pm_usage_cnt;		/* usage counter for autosuspend */
+	u32 quirks;			/* quirks of the whole device */
 #ifdef CONFIG_PM
 	struct delayed_work autosuspend; /* for delayed autosuspends */
 	struct mutex pm_mutex;		/* protects PM operations */

include/linux/usb/quirks.h

+/*
+ * This file holds the definitions of quirks found in USB devices.
+ * Only quirks that affect the whole device, not an interface,
+ * belong here.
+ */
+
+/* device must not be autosuspended */
+#define USB_QUIRK_NO_AUTOSUSPEND	0x00000001
+
+/* string descriptors must not be fetched using a 255-byte read */
+#define USB_QUIRK_STRING_FETCH_255	0x00000002