ChangeSet 1.808.2.4, 2002/10/21 23:22:52-07:00, dbrownell@users.sourceforge.net

[PATCH] usb: problem clearing halts

This is a slightly cleaned up version of that earlier patch:

- Makes both copies of the clear_halt() logic know that
   usb_pipein() returns boolean (zero/not) not integer (0/1).
   This resolves a problem folk have had with usb-storage.
   (I looked at kernel uses of usb_pipein and it really was
   only the clear_halt logic that cares.)

- Removes some code from the "standard" version; no point
   in Linux expecting devices to do something neither Microsoft
   nor Apple will test for.


diff -Nru a/drivers/usb/core/message.c b/drivers/usb/core/message.c
--- a/drivers/usb/core/message.c	Mon Oct 28 13:56:25 2002
+++ b/drivers/usb/core/message.c	Mon Oct 28 13:56:25 2002
@@ -686,8 +686,9 @@
  * as reported by URB completion status.  Endpoints that are halted are
  * sometimes referred to as being "stalled".  Such endpoints are unable
  * to transmit or receive data until the halt status is cleared.  Any URBs
- * queued queued for such an endpoint should normally be unlinked before
- * clearing the halt condition.
+ * queued for such an endpoint should normally be unlinked by the driver
+ * before clearing the halt condition, as described in sections 5.7.5
+ * and 5.8.5 of the USB 2.0 spec.
  *
  * Note that control and isochronous endpoints don't halt, although control
  * endpoints report "protocol stall" (for unsupported requests) using the
@@ -701,48 +702,34 @@
 int usb_clear_halt(struct usb_device *dev, int pipe)
 {
 	int result;
-	__u16 status;
-	unsigned char *buffer;
-	int endp=usb_pipeendpoint(pipe)|(usb_pipein(pipe)<<7);
-
-/*
-	if (!usb_endpoint_halted(dev, endp & 0x0f, usb_endpoint_out(endp)))
-		return 0;
-*/
-
+	int endp = usb_pipeendpoint(pipe);
+	
+	if (usb_pipein (pipe))
+		endp |= USB_DIR_IN;
+
+	/* we don't care if it wasn't halted first. in fact some devices
+	 * (like some ibmcam model 1 units) seem to expect hosts to make
+	 * this request for iso endpoints, which can't halt!
+	 */
 	result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
 		USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT, 0, endp, NULL, 0,
 		HZ * USB_CTRL_SET_TIMEOUT);
 
-	/* don't clear if failed */
-	if (result < 0)
-		return result;
-
-	buffer = kmalloc(sizeof(status), GFP_KERNEL);
-	if (!buffer) {
-		err("unable to allocate memory for configuration descriptors");
-		return -ENOMEM;
-	}
-
-	result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
-		USB_REQ_GET_STATUS, USB_DIR_IN | USB_RECIP_ENDPOINT, 0, endp,
-		// FIXME USB_CTRL_GET_TIMEOUT, yes?  why not usb_get_status() ?
-		buffer, sizeof(status), HZ * USB_CTRL_SET_TIMEOUT);
-
-	memcpy(&status, buffer, sizeof(status));
-	kfree(buffer);
-
+	/* don't un-halt or force to DATA0 except on success */
 	if (result < 0)
 		return result;
 
-	if (le16_to_cpu(status) & 1)
-		return -EPIPE;		/* still halted */
-
-	usb_endpoint_running(dev, usb_pipeendpoint(pipe), usb_pipeout(pipe));
-
-	/* toggle is reset on clear */
+	/* NOTE:  seems like Microsoft and Apple don't bother verifying
+	 * the clear "took", so some devices could lock up if you check...
+	 * such as the Hagiwara FlashGate DUAL.  So we won't bother.
+	 *
+	 * NOTE:  make sure the logic here doesn't diverge much from
+	 * the copy in usb-storage, for as long as we need two copies.
+	 */
 
+	/* toggle was reset by the clear, then ep was reactivated */
 	usb_settoggle(dev, usb_pipeendpoint(pipe), usb_pipeout(pipe), 0);
+	usb_endpoint_running(dev, usb_pipeendpoint(pipe), usb_pipeout(pipe));
 
 	return 0;
 }
diff -Nru a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c
--- a/drivers/usb/storage/transport.c	Mon Oct 28 13:56:25 2002
+++ b/drivers/usb/storage/transport.c	Mon Oct 28 13:56:25 2002
@@ -518,7 +518,10 @@
 int usb_stor_clear_halt(struct us_data *us, unsigned int pipe)
 {
 	int result;
-	int endp = usb_pipeendpoint(pipe) | (usb_pipein(pipe) << 7);
+	int endp = usb_pipeendpoint(pipe);
+
+	if (usb_pipein (pipe))
+		endp |= USB_DIR_IN;
 
 	result = usb_stor_control_msg(us, us->send_ctrl_pipe,
 		USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT, 0,