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Commit e009f1b2 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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UHCI: Fix problem caused by lack of terminating QH 



This patch (as871) fixes a problem introduced by an earlier change.
It turns out that some systems really do need to have a terminating
skeleton QH present whenever FSBR is on.  I don't know any way to tell
which systems do need it and which don't; the easiest answer is to
have it there always.

This fixes the NumLock-hang bug reported by Jiri Slaby.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent e0f2e3a0

drivers/usb/host/uhci-debug.c

+15 −11
Original line number Diff line number Diff line
@@ -145,7 +145,8 @@ static int uhci_show_urbp(struct urb_priv *urbp, char *buf, int len, int space) 
	return out - buf;

}



static int uhci_show_qh(struct uhci_qh *qh, char *buf, int len, int space)

static int uhci_show_qh(struct uhci_hcd *uhci,

		struct uhci_qh *qh, char *buf, int len, int space)

{

	char *out = buf;

	int i, nurbs;
@@ -190,6 +191,9 @@ static int uhci_show_qh(struct uhci_qh *qh, char *buf, int len, int space) 


	if (list_empty(&qh->queue)) {

		out += sprintf(out, "%*s  queue is empty\n", space, "");

		if (qh == uhci->skel_async_qh)

			out += uhci_show_td(uhci->term_td, out,

					len - (out - buf), 0);

	} else {

		struct urb_priv *urbp = list_entry(qh->queue.next,

				struct urb_priv, node);
@@ -343,6 +347,7 @@ static int uhci_sprint_schedule(struct uhci_hcd *uhci, char *buf, int len) 
	struct list_head *tmp, *head;

	int nframes, nerrs;

	__le32 link;

	__le32 fsbr_link;



	static const char * const qh_names[] = {

		"unlink", "iso", "int128", "int64", "int32", "int16",
@@ -424,21 +429,22 @@ static int uhci_sprint_schedule(struct uhci_hcd *uhci, char *buf, int len) 


	out += sprintf(out, "Skeleton QHs\n");



	fsbr_link = 0;

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

		int cnt = 0;

		__le32 fsbr_link = 0;



		qh = uhci->skelqh[i];

		out += sprintf(out, "- skel_%s_qh\n", qh_names[i]); \

		out += uhci_show_qh(qh, out, len - (out - buf), 4);

		out += uhci_show_qh(uhci, qh, out, len - (out - buf), 4);



		/* Last QH is the Terminating QH, it's different */

		if (i == SKEL_TERM) {

			if (qh_element(qh) != LINK_TO_TD(uhci->term_td))

				out += sprintf(out, "    skel_term_qh element is not set to term_td!\n");

			if (link == LINK_TO_QH(uhci->skel_term_qh))

			link = fsbr_link;

			if (!link)

				link = LINK_TO_QH(uhci->skel_term_qh);

			goto check_qh_link;

			continue;

		}



		head = &qh->node;
@@ -448,7 +454,7 @@ static int uhci_sprint_schedule(struct uhci_hcd *uhci, char *buf, int len) 
			qh = list_entry(tmp, struct uhci_qh, node);

			tmp = tmp->next;

			if (++cnt <= 10)

				out += uhci_show_qh(qh, out,

				out += uhci_show_qh(uhci, qh, out,

						len - (out - buf), 4);

			if (!fsbr_link && qh->skel >= SKEL_FSBR)

				fsbr_link = LINK_TO_QH(qh);
@@ -463,8 +469,6 @@ static int uhci_sprint_schedule(struct uhci_hcd *uhci, char *buf, int len) 
			link = LINK_TO_QH(uhci->skel_async_qh);

		else if (!uhci->fsbr_is_on)

			;

		else if (fsbr_link)

			link = fsbr_link;

		else

			link = LINK_TO_QH(uhci->skel_term_qh);

check_qh_link:
@@ -573,8 +577,8 @@ static const struct file_operations uhci_debug_operations = { 
static inline void lprintk(char *buf)

{}



static inline int uhci_show_qh(struct uhci_qh *qh, char *buf,

		int len, int space)

static inline int uhci_show_qh(struct uhci_hcd *uhci,

		struct uhci_qh *qh, char *buf, int len, int space)

{

	return 0;

}

drivers/usb/host/uhci-hcd.c

+2 −1
Original line number Diff line number Diff line
@@ -632,7 +632,8 @@ static int uhci_start(struct usb_hcd *hcd) 
	 */

	for (i = SKEL_ISO + 1; i < SKEL_ASYNC; ++i)

		uhci->skelqh[i]->link = LINK_TO_QH(uhci->skel_async_qh);

	uhci->skel_async_qh->link = uhci->skel_term_qh->link = UHCI_PTR_TERM;

	uhci->skel_async_qh->link = UHCI_PTR_TERM;

	uhci->skel_term_qh->link = LINK_TO_QH(uhci->skel_term_qh);



	/* This dummy TD is to work around a bug in Intel PIIX controllers */

	uhci_fill_td(uhci->term_td, 0, uhci_explen(0) |

drivers/usb/host/uhci-q.c

+24 −70
Original line number Diff line number Diff line
@@ -45,43 +45,27 @@ static inline void uhci_clear_next_interrupt(struct uhci_hcd *uhci) 
 */

static void uhci_fsbr_on(struct uhci_hcd *uhci)

{

	struct uhci_qh *fsbr_qh, *lqh, *tqh;

	struct uhci_qh *lqh;



	/* The terminating skeleton QH always points back to the first

	 * FSBR QH.  Make the last async QH point to the terminating

	 * skeleton QH. */

	uhci->fsbr_is_on = 1;

	lqh = list_entry(uhci->skel_async_qh->node.prev,

			struct uhci_qh, node);



	/* Find the first FSBR QH.  Linear search through the list is

	 * acceptable because normally FSBR gets turned on as soon as

	 * one QH needs it. */

	fsbr_qh = NULL;

	list_for_each_entry_reverse(tqh, &uhci->skel_async_qh->node, node) {

		if (tqh->skel < SKEL_FSBR)

			break;

		fsbr_qh = tqh;

	}



	/* No FSBR QH means we must insert the terminating skeleton QH */

	if (!fsbr_qh) {

		uhci->skel_term_qh->link = LINK_TO_QH(uhci->skel_term_qh);

		wmb();

		lqh->link = uhci->skel_term_qh->link;



	/* Otherwise loop the last QH to the first FSBR QH */

	} else

		lqh->link = LINK_TO_QH(fsbr_qh);

	lqh->link = LINK_TO_QH(uhci->skel_term_qh);

}



static void uhci_fsbr_off(struct uhci_hcd *uhci)

{

	struct uhci_qh *lqh;



	/* Remove the link from the last async QH to the terminating

	 * skeleton QH. */

	uhci->fsbr_is_on = 0;

	lqh = list_entry(uhci->skel_async_qh->node.prev,

			struct uhci_qh, node);



	/* End the async list normally and unlink the terminating QH */

	lqh->link = uhci->skel_term_qh->link = UHCI_PTR_TERM;

	lqh->link = UHCI_PTR_TERM;

}



static void uhci_add_fsbr(struct uhci_hcd *uhci, struct urb *urb)
@@ -464,9 +448,8 @@ static void link_interrupt(struct uhci_hcd *uhci, struct uhci_qh *qh) 
 */

static void link_async(struct uhci_hcd *uhci, struct uhci_qh *qh)

{

	struct uhci_qh *pqh, *lqh;

	struct uhci_qh *pqh;

	__le32 link_to_new_qh;

	__le32 *extra_link = &link_to_new_qh;



	/* Find the predecessor QH for our new one and insert it in the list.

	 * The list of QHs is expected to be short, so linear search won't
@@ -476,31 +459,17 @@ static void link_async(struct uhci_hcd *uhci, struct uhci_qh *qh) 
			break;

	}

	list_add(&qh->node, &pqh->node);

	qh->link = pqh->link;



	link_to_new_qh = LINK_TO_QH(qh);



	/* If this is now the first FSBR QH, take special action */

	if (uhci->fsbr_is_on && pqh->skel < SKEL_FSBR &&

			qh->skel >= SKEL_FSBR) {

		lqh = list_entry(uhci->skel_async_qh->node.prev,

				struct uhci_qh, node);



		/* If the new QH is also the last one, we must unlink

		 * the terminating skeleton QH and make the new QH point

		 * back to itself. */

		if (qh == lqh) {

			qh->link = link_to_new_qh;

			extra_link = &uhci->skel_term_qh->link;



		/* Otherwise the last QH must point to the new QH */

		} else

			extra_link = &lqh->link;

	}



	/* Link it into the schedule */

	qh->link = pqh->link;

	wmb();

	*extra_link = pqh->link = link_to_new_qh;

	link_to_new_qh = LINK_TO_QH(qh);

	pqh->link = link_to_new_qh;



	/* If this is now the first FSBR QH, link the terminating skeleton

	 * QH to it. */

	if (pqh->skel < SKEL_FSBR && qh->skel >= SKEL_FSBR)

		uhci->skel_term_qh->link = link_to_new_qh;

}



/*
@@ -561,31 +530,16 @@ static void unlink_interrupt(struct uhci_hcd *uhci, struct uhci_qh *qh) 
 */

static void unlink_async(struct uhci_hcd *uhci, struct uhci_qh *qh)

{

	struct uhci_qh *pqh, *lqh;

	struct uhci_qh *pqh;

	__le32 link_to_next_qh = qh->link;



	pqh = list_entry(qh->node.prev, struct uhci_qh, node);

	pqh->link = link_to_next_qh;



	/* If this is the first FSBQ QH, take special action */

	if (uhci->fsbr_is_on && pqh->skel < SKEL_FSBR &&

			qh->skel >= SKEL_FSBR) {

		lqh = list_entry(uhci->skel_async_qh->node.prev,

				struct uhci_qh, node);



		/* If this QH is also the last one, we must link in

		 * the terminating skeleton QH. */

		if (qh == lqh) {

			link_to_next_qh = LINK_TO_QH(uhci->skel_term_qh);

	/* If this was the old first FSBR QH, link the terminating skeleton

	 * QH to the next (new first FSBR) QH. */

	if (pqh->skel < SKEL_FSBR && qh->skel >= SKEL_FSBR)

		uhci->skel_term_qh->link = link_to_next_qh;

			wmb();

			qh->link = link_to_next_qh;



		/* Otherwise the last QH must point to the new first FSBR QH */

		} else

			lqh->link = link_to_next_qh;

	}



	pqh->link = link_to_next_qh;

	mb();

}
@@ -1217,7 +1171,7 @@ static int uhci_result_common(struct uhci_hcd *uhci, struct urb *urb) 


				if (debug > 1 && errbuf) {

					/* Print the chain for debugging */

					uhci_show_qh(urbp->qh, errbuf,

					uhci_show_qh(uhci, urbp->qh, errbuf,

							ERRBUF_LEN, 0);

					lprintk(errbuf);

				}