USB: EHCI: changes related to qh_refresh()
This patch (as1638) makes several changes to the ehci-hcd driver, all
related to the qh_refresh() function. This function must be called
whenever an idle QH gets linked back into either the async or the
periodic schedule.
Change a BUG_ON() in the qh_update routine to a WARN_ON().
Since this code runs in atomic context, a BUG_ON() would
immediately freeze the whole system.
Remove two unneeded calls to qh_refresh(), one when a QH is
initialized and one when a QH becomes idle. Adjust the
adjacent comments accordingly.
Move the qh_refresh() and qh_link_periodic() calls for new
interrupt URBs to after the new TDs have been added.
As a result of the previous two changes, qh_refresh() is never
called when the qtd_list is empty. The corresponding check in
qh_refresh() can be removed, along with an indentation level.
These changes should not cause any alteration of behavior.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index b476daf..66259dc 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -792,7 +792,6 @@
unsigned frame; /* 0..(qh->period - 1), or NO_FRAME */
struct ehci_qh_hw *hw = qh->hw;
- qh_refresh(ehci, qh);
hw->hw_next = EHCI_LIST_END(ehci);
frame = qh->start;
@@ -844,8 +843,6 @@
} else
ehci_dbg (ehci, "reused qh %p schedule\n", qh);
- /* stuff into the periodic schedule */
- qh_link_periodic(ehci, qh);
done:
return status;
}
@@ -891,6 +888,12 @@
qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
BUG_ON (qh == NULL);
+ /* stuff into the periodic schedule */
+ if (qh->qh_state == QH_STATE_IDLE) {
+ qh_refresh(ehci, qh);
+ qh_link_periodic(ehci, qh);
+ }
+
/* ... update usbfs periodic stats */
ehci_to_hcd(ehci)->self.bandwidth_int_reqs++;