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Commit c39772d8 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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USB: allow retry on descriptor fetch errors 



This patch (as964) was suggested by Steffen Koepf.  It makes
usb_get_descriptor() retry on all errors other than ETIMEDOUT, instead
of only on EPIPE.  This helps with some devices.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
CC: stable <stable@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 3b79cc26

drivers/usb/core/message.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -637,12 +637,12 @@ int usb_get_descriptor(struct usb_device *dev, unsigned char type, unsigned char 
	memset(buf,0,size);	// Make sure we parse really received data

	memset(buf,0,size);	// Make sure we parse really received data





	for (i = 0; i < 3; ++i) {

	for (i = 0; i < 3; ++i) {

		/* retry on length 0 or stall; some devices are flakey */

		/* retry on length 0 or error; some devices are flakey */

		result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),

		result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),

				USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,

				USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,

				(type << 8) + index, 0, buf, size,

				(type << 8) + index, 0, buf, size,

				USB_CTRL_GET_TIMEOUT);

				USB_CTRL_GET_TIMEOUT);

		if (result == 0 || result == -EPIPE)

		if (result <= 0 && result != -ETIMEDOUT)

			continue;

			continue;

		if (result > 1 && ((u8 *)buf)[1] != type) {

		if (result > 1 && ((u8 *)buf)[1] != type) {

			result = -EPROTO;

			result = -EPROTO;