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UHCI: Fix problem caused by lack of terminating QH

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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>
Tento commit je obsažen v:
Alan Stern
2007-03-19 15:31:42 -04:00
odevzdal Greg Kroah-Hartman
rodič e0f2e3a06b
revize e009f1b202
3 změnil soubory, kde provedl 41 přidání a 82 odebrání
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94
drivers/usb/host/uhci-q.c
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@@ -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);
/* 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();
}
@@ -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);
}