diff options
author | Alan Stern <stern@rowland.harvard.edu> | 2007-03-19 20:31:42 +0100 |
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committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-03-26 23:17:48 +0200 |
commit | e009f1b202219c62ea7e277adbb953d703dac983 (patch) | |
tree | f4eddb5808258c2b1f7504b4866a65c8a0a8434e /drivers/usb/host/uhci-q.c | |
parent | Linux 2.6.21-rc5 (diff) | |
download | linux-e009f1b202219c62ea7e277adbb953d703dac983.tar.xz linux-e009f1b202219c62ea7e277adbb953d703dac983.zip |
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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/host/uhci-q.c')
-rw-r--r-- | drivers/usb/host/uhci-q.c | 94 |
1 files changed, 24 insertions, 70 deletions
diff --git a/drivers/usb/host/uhci-q.c b/drivers/usb/host/uhci-q.c index f4ebdb3e488f..19a0cc02b9a2 100644 --- a/drivers/usb/host/uhci-q.c +++ b/drivers/usb/host/uhci-q.c @@ -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); } |