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USB: EHCI: add separate IAA watchdog timer

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This patch (as1028) was mostly written by David Brownell; I made only
a few changes (extra log info and a small bug fix -- which might
account for why David's version had to be reverted).  It adds a new
watchdog timer to the ehci-hcd driver to be used exclusively for
detecting lost or missing IAA notifications.

Previously a shared timer had been used, which may have led to some
problems as reported by Christian Hoffmann.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern
2007-12-11 16:05:30 -05:00
committed by Greg Kroah-Hartman
parent 2e2eb83ffd
commit 07d29b63ef
6 changed files with 75 additions and 38 deletions
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22
drivers/usb/host/ehci.h
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@@ -74,7 +74,6 @@ struct ehci_hcd { /* one per controller */
/* async schedule support */
struct ehci_qh *async;
struct ehci_qh *reclaim;
unsigned reclaim_ready : 1;
unsigned scanning : 1;
/* periodic schedule support */
@@ -105,6 +104,7 @@ struct ehci_hcd { /* one per controller */
struct dma_pool *itd_pool; /* itd per iso urb */
struct dma_pool *sitd_pool; /* sitd per split iso urb */
struct timer_list iaa_watchdog;
struct timer_list watchdog;
unsigned long actions;
unsigned stamp;
@@ -148,9 +148,21 @@ static inline struct usb_hcd *ehci_to_hcd (struct ehci_hcd *ehci)
}
static inline void
iaa_watchdog_start(struct ehci_hcd *ehci)
{
WARN_ON(timer_pending(&ehci->iaa_watchdog));
mod_timer(&ehci->iaa_watchdog,
jiffies + msecs_to_jiffies(EHCI_IAA_MSECS));
}
static inline void iaa_watchdog_done(struct ehci_hcd *ehci)
{
del_timer(&ehci->iaa_watchdog);
}
enum ehci_timer_action {
TIMER_IO_WATCHDOG,
TIMER_IAA_WATCHDOG,
TIMER_ASYNC_SHRINK,
TIMER_ASYNC_OFF,
};
@@ -168,9 +180,6 @@ timer_action (struct ehci_hcd *ehci, enum ehci_timer_action action)
unsigned long t;
switch (action) {
case TIMER_IAA_WATCHDOG:
t = EHCI_IAA_JIFFIES;
break;
case TIMER_IO_WATCHDOG:
t = EHCI_IO_JIFFIES;
break;
@@ -187,8 +196,7 @@ timer_action (struct ehci_hcd *ehci, enum ehci_timer_action action)
// async queue SHRINK often precedes IAA. while it's ready
// to go OFF neither can matter, and afterwards the IO
// watchdog stops unless there's still periodic traffic.
if (action != TIMER_IAA_WATCHDOG
&& t > ehci->watchdog.expires
if (time_before_eq(t, ehci->watchdog.expires)
&& timer_pending (&ehci->watchdog))
return;
mod_timer (&ehci->watchdog, t);