USB: add quirk to avoid config and interface strings

Apparently the Configuration and Interface strings aren't used as
often as the Vendor, Product, and Serial strings.  In at least one
device (a Saitek Cyborg Gold 3D joystick), attempts to read the
Configuration string cause the device to stop responding to Control
requests.

This patch (as1226) adds a quirks flag, telling the kernel not to
read a device's Configuration or Interface strings, together with a
new quirk for the offending joystick.

Reported-by: Melchior FRANZ <melchior.franz@gmail.com>
Tested-by: Melchior FRANZ <melchior.franz@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>  [2.6.28 and 2.6.29, nothing earlier]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 9 insertions, 2 deletions

diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 49e7f56e0d7f..3922fa915ed2 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1719,7 +1719,8 @@ free_interfaces:
         }
         kfree(new_interfaces);
 
-        if (cp->string == NULL)
+        if (cp->string == NULL &&
+                        !(dev->quirks & USB_QUIRK_CONFIG_INTF_STRINGS))
                 cp->string = usb_cache_string(dev, cp->desc.iConfiguration);
 
         /* Now that all the interfaces are set up, register them
diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
index c070b34b669d..ab93918d9207 100644
--- a/drivers/usb/core/quirks.c
+++ b/drivers/usb/core/quirks.c
@@ -54,6 +54,10 @@ static const struct usb_device_id usb_quirk_list[] = {
         { USB_DEVICE(0x0638, 0x0a13), .driver_info =
           USB_QUIRK_STRING_FETCH_255 },
 
+        /* Saitek Cyborg Gold Joystick */
+        { USB_DEVICE(0x06a3, 0x0006), .driver_info =
+                        USB_QUIRK_CONFIG_INTF_STRINGS },
+
         /* M-Systems Flash Disk Pioneers */
         { USB_DEVICE(0x08ec, 0x1000), .driver_info = USB_QUIRK_RESET_RESUME },
 
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index 4cc2456ef3be..c66789197927 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -13,6 +13,7 @@
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/usb.h>
+#include <linux/usb/quirks.h>
 #include "usb.h"
 
 /* Active configuration fields */
@@ -813,7 +814,8 @@ int usb_create_sysfs_intf_files(struct usb_interface *intf)
         if (intf->sysfs_files_created || intf->unregistering)
                 return 0;
 
-        if (alt->string == NULL)
+        if (alt->string == NULL &&
+                        !(udev->quirks & USB_QUIRK_CONFIG_INTF_STRINGS))
                 alt->string = usb_cache_string(udev, alt->desc.iInterface);
         if (alt->string)
                 retval = device_create_file(&intf->dev, &dev_attr_interface);