Skip to content

Commit

Permalink
UHCI: Fix problem caused by lack of terminating QH
Browse files Browse the repository at this point in the history 
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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  • Loading branch information
Alan Stern authored and Greg Kroah-Hartman committed Mar 26, 2007
1 parent e0f2e3a commit e009f1b
Show file tree
Hide file tree
Showing 3 changed files with 41 additions and 82 deletions.
26 changes: 15 additions & 11 deletions drivers/usb/host/uhci-debug.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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",
Expand Down Expand Up @@ -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))
goto check_qh_link;
continue;
link = fsbr_link;
if (!link)
link = LINK_TO_QH(uhci->skel_term_qh);
goto check_qh_link;
}

head = &qh->node;
Expand All @@ -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);
Expand All @@ -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:
Expand Down Expand Up @@ -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;
}
Expand Down
3 changes: 2 additions & 1 deletion drivers/usb/host/uhci-hcd.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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) |
Expand Down
94 changes: 24 additions & 70 deletions drivers/usb/host/uhci-q.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand Down Expand Up @@ -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
Expand All @@ -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;
}

/*
Expand Down Expand Up @@ -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);

/* 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);
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;

/* 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;
mb();
}

Expand Down Expand Up @@ -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);
}
Expand Down

0 comments on commit e009f1b

Please sign in to comment.