Re: [linux-usb-devel] [PATCH] fix some hubs and hid devices at startup

[Johannes Erdfelt <johannes@erdfelt.com>]

On Wed, May 15, 2002, Olaf Hering <olh@suse.de> wrote:
> On Fri, Mar 15, Greg KH wrote:
> 
> > On Thu, Mar 14, 2002 at 02:21:47PM +0100, Olaf Hering wrote:
> > > > The problem looks like the usbdevfs calls are happening at the same time
> > > > the hid driver is also talking to the device.
> > > > 
> > > > Olaf, is this what your log messages show?
> > > 
> > > It seems so. I think a more correct fix would be a lock in the usbcore
> > > code to hold usbdevfs requests when "some bus action" is going on, like
> > > this renumbering. You said there is no lock right now for this case?
> > 
> > This is correct and has been on the list of things to fix in the usb
> > code for a while.
> 
> What is the status of this bug in the hotplug related functions? We
> added a "sleep 3" in the add routing in usb.rc, but that can only be a
> workaround.
> 
> My idea was that we queue the hotplug events somehow and wait for all
> "bus traffic" to complete, the stuff that occours when the usb-uhci
> driver is loaded. Something like
> insmod usbcore;insmod usb-uhci;modprobe hid;insmod keybdev;insmod mousedev
> should work. And it did not with 2.4.19pre2/3, I got timeouts. However,
> typing the commands manually to get some delay, and it worked. So I
> think that it is not strictly related to usbdevfs, that might be another
> bug.
> 
> However, after reading the whole thread again, it seems that queuing the
> events is maybe not the best solution. What should be done to get this
> fixed? (The delay and locking should be in the kernel and not in the
> hotplug package).

Well, it shouldn't be giving you back ETIMEDOUT. That's indicitive of
another bug, not the queueing.

However, it looks like uhci.c (and probably usb-uhci.c too since the
code was based on it) didn't correctly match control pipe's and prevent
2 URB's from being queued, 1 in and 1 out.

Can you try this patch?

It should atleast start returning -ENXIO (-6 on x86).

JE

--- linux-2.4.19-pre8.orig/drivers/usb/uhci.c	Wed May 15 13:29:27 2002
+++ linux-2.4.19-pre8/drivers/usb/uhci.c	Wed May 15 13:27:52 2002
@@ -1470,9 +1470,14 @@
 
 		tmp = tmp->next;
 
-		if (u->dev = urb->dev && u->pipe = urb->pipe &&
-		    u->status = -EINPROGRESS)
-			return u;
+		if (u->dev = urb->dev && u->status = -EINPROGRESS) {
+			/* For control, ignore the direction */
+			if (usb_pipecontrol(urb->pipe) &&
+			    (u->pipe & ~USB_DIR_IN) = (urb->pipe & ~USB_DIR_IN))
+				return u;
+			else if (u->pipe = urb->pipe)
+				return u;
+		}
 	}
 
 	return NULL;

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