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USB: ehci - fix timer regression 

This patch fixes a regression in the EHCI driver's TIMER_IO_WATCHDOG
behavior.  The patch "USB: EHCI: add separate IAA watchdog timer" changed
how that timer is handled, so that short timeouts on the remaining
timer (unfortunately, overloaded) would never be used.

This takes a more direct approach, reorganizing the code slightly to
be explicit about only the I/O watchdog role now being overridable.
It also replaces a now-obsolete comment describing older timer behavior.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Leonid <leonidv11@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
hifive-unleashed-5.1
David Brownell 2008-06-13 23:56:48 -07:00 committed by Greg Kroah-Hartman
parent 4b828abed2
commit 056761e55c
1 changed files with 10 additions and 9 deletions
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19
drivers/usb/host/ehci.h
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@ -177,6 +177,15 @@ timer_action_done (struct ehci_hcd *ehci, enum ehci_timer_action action)
static inline void
timer_action (struct ehci_hcd *ehci, enum ehci_timer_action action)
{
/* Don't override timeouts which shrink or (later) disable
* the async ring; just the I/O watchdog. Note that if a
* SHRINK were pending, OFF would never be requested.
*/
if (timer_pending(&ehci->watchdog)
&& ((BIT(TIMER_ASYNC_SHRINK) | BIT(TIMER_ASYNC_OFF))
& ehci->actions))
return;
if (!test_and_set_bit (action, &ehci->actions)) {
unsigned long t;
@ -192,15 +201,7 @@ timer_action (struct ehci_hcd *ehci, enum ehci_timer_action action)
t = EHCI_SHRINK_JIFFIES;
break;
}
t += jiffies;
// all timings except IAA watchdog can be overridden.
// 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 (time_before_eq(t, ehci->watchdog.expires)
&& timer_pending (&ehci->watchdog))
return;
mod_timer (&ehci->watchdog, t);
mod_timer(&ehci->watchdog, t + jiffies);
}
}