The following reply was made to PR kern/34070; it has been noted by GNATS.

From: Matthias Drochner <M.Drochner@fz-juelich.de>
To: Iain Hibbert <plunky@rya-online.net>
Cc: gnats-bugs@NetBSD.org, kern-bug-people@NetBSD.org,
	gnats-admin@NetBSD.org, netbsd-bugs@NetBSD.org, wulf@NetBSD.org
Subject: Re: kern/34070: btconfig: SIOCSBTFLAGS: Resource temporarily 
 unavailable
Date: Mon, 27 Nov 2006 21:18:27 +0100

 This is a multipart MIME message.
 
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 plunky@rya-online.net said:
 > Not that I can suggest masking such a bug by conforming to a hidden
 > magic number (I wonder if 16 is a generally used value) 
 
 I think I have a fix which is not too invasive but still
 halfway clean: kill the code which tries to compute the
 toggle after a short transfer. To fix it to deal with block
 alignment would make it even more expensive; reading
 the updated toggle from the descriptor is cheaper imho.
 The appended patch makes ubt work as far as I could check
 without a device.
 
 best regards
 Matthias
 
 
 
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 Content-Type: text/plain ; name="ehci.txt"; charset=us-ascii
 Content-Description: ehci.txt
 Content-Disposition: attachment; filename="ehci.txt"
 
 # 
 # 
 # patch "sys/dev/usb/ehci.c"
 #  from [9719bcf04cebd0079d8570b78d59c267164aa1d1]
 #    to [7ae22e8f8c034f1a4b891e85526ec1e137128a51]
 # 
 ============================================================
 --- sys/dev/usb/ehci.c	9719bcf04cebd0079d8570b78d59c267164aa1d1
 +++ sys/dev/usb/ehci.c	7ae22e8f8c034f1a4b891e85526ec1e137128a51
 @@ -773,7 +773,6 @@ ehci_idone(struct ehci_xfer *ex)
  	ehci_soft_qtd_t *sqtd, *lsqtd;
  	u_int32_t status = 0, nstatus = 0;
  	int actlen;
 -	uint pkts_left;
  
  	DPRINTFN(/*12*/2, ("ehci_idone: ex=%p\n", ex));
  #ifdef DIAGNOSTIC
 @@ -823,10 +822,13 @@ ehci_idone(struct ehci_xfer *ex)
  	 * If there are left over TDs we need to update the toggle.
  	 * The default pipe doesn't need it since control transfers
  	 * start the toggle at 0 every time.
 +	 * For a short transfer we need to update the toggle for the missing
 +	 * packets within the qTD.
  	 */
 -	if (sqtd != lsqtd->nextqtd &&
 +	if ((sqtd != lsqtd->nextqtd || EHCI_QTD_GET_BYTES(status)) &&
  	    xfer->pipe->device->default_pipe != xfer->pipe) {
 -		printf("ehci_idone: need toggle update status=%08x nstatus=%08x\n", status, nstatus);
 +		DPRINTFN(2, ("ehci_idone: need toggle update "
 +			     "status=%08x nstatus=%08x\n", status, nstatus));
  #if 0
  		ehci_dump_sqh(epipe->sqh);
  		ehci_dump_sqtds(ex->sqtdstart);
 @@ -834,14 +836,6 @@ ehci_idone(struct ehci_xfer *ex)
  		epipe->nexttoggle = EHCI_QTD_GET_TOGGLE(nstatus);
  	}
  
 -	/*
 -	 * For a short transfer we need to update the toggle for the missing
 -	 * packets within the qTD.
 -	 */
 -	pkts_left = EHCI_QTD_GET_BYTES(status) /
 -	    UGETW(xfer->pipe->endpoint->edesc->wMaxPacketSize);
 -	epipe->nexttoggle ^= pkts_left % 2;
 -
  	DPRINTFN(/*10*/2, ("ehci_idone: len=%d, actlen=%d, status=0x%x\n",
  			   xfer->length, actlen, status));
  	xfer->actlen = actlen;
 
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