diff options
| author | Alan Stern <stern@rowland.harvard.edu> | 2009-02-20 16:33:08 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-03-16 17:32:03 -0700 |
| commit | 2ad66518a8fc1cef4968bbe2fd65f37d9a177dd1 (patch) | |
| tree | 91a67f546422daae708edebd986f8336f0654ff0 | |
| parent | 8ad59c65f7e043b34f8bc83a1e5f8cb6796c22be (diff) | |
USB: usb_get_string should check the descriptor type
commit 67f5a4ba9741fcef3f4db3509ad03565d9e33af2 upstream.
This patch (as1218) fixes a problem with a radio-control joystick used
in the "walkera 4#3" helicopter. This device responds to the initial
Get-String-Descriptor request for string 0 (which is really the list
of supported languages) by sending its config descriptor! The
usb_get_string() routine needs to check whether it got the right
type of descriptor.
Oddly enough, this sort of check is already present in
usb_get_descriptor(). The patch changes the error code from -EPROTO
to -ENODATA, because -EPROTO shows up in so many other contexts to
indicate a hardware failure rather than a firmware error.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Guillermo Jarabo <williamjap@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/usb/core/message.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index 8497f636406..e00127c4e8e 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -651,7 +651,7 @@ int usb_get_descriptor(struct usb_device *dev, unsigned char type, if (result <= 0 && result != -ETIMEDOUT) continue; if (result > 1 && ((u8 *)buf)[1] != type) { - result = -EPROTO; + result = -ENODATA; continue; } break; @@ -694,8 +694,13 @@ static int usb_get_string(struct usb_device *dev, unsigned short langid, USB_REQ_GET_DESCRIPTOR, USB_DIR_IN, (USB_DT_STRING << 8) + index, langid, buf, size, USB_CTRL_GET_TIMEOUT); - if (!(result == 0 || result == -EPIPE)) - break; + if (result == 0 || result == -EPIPE) + continue; + if (result > 1 && ((u8 *) buf)[1] != USB_DT_STRING) { + result = -ENODATA; + continue; + } + break; } return result; } |