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USB: EHCI: reorganize ehci_iaa_watchdog()

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This patch (as1635) rearranges the control-flow logic in
ehci_iaa_watchdog() slightly to agree better with the comments.  It
also changes a verbose-debug message to a regular debug message.
Expiration of the IAA watchdog is an unusual event and can lead to
problems; we need to know about it if it happens during debugging.  It
should not be necessary to set a "verbose" compilation option.

No behavioral changes other than the debug message.  Lots of apparent
changes to the source text, though, because the indentation level was
decreased.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alan Stern 2013-03-18 12:05:19 -04:00 committed by Greg Kroah-Hartman
parent 4dd405a4b0
commit 60fd4aa742
1 changed files with 24 additions and 27 deletions
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51
drivers/usb/host/ehci-timer.c
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@ -295,8 +295,7 @@ static void end_free_itds(struct ehci_hcd *ehci)
/* Handle lost (or very late) IAA interrupts */
static void ehci_iaa_watchdog(struct ehci_hcd *ehci)
{
if (ehci->rh_state != EHCI_RH_RUNNING)
return;
u32 cmd, status;
/*
* Lost IAA irqs wedge things badly; seen first with a vt8235.
@ -304,34 +303,32 @@ static void ehci_iaa_watchdog(struct ehci_hcd *ehci)
* (a) SMP races against real IAA firing and retriggering, and
* (b) clean HC shutdown, when IAA watchdog was pending.
*/
if (ehci->async_iaa) {
u32 cmd, status;
if (!ehci->async_iaa || ehci->rh_state != EHCI_RH_RUNNING)
return;
/* If we get here, IAA is *REALLY* late. It's barely
* conceivable that the system is so busy that CMD_IAAD
* is still legitimately set, so let's be sure it's
* clear before we read STS_IAA. (The HC should clear
* CMD_IAAD when it sets STS_IAA.)
*/
cmd = ehci_readl(ehci, &ehci->regs->command);
/* If we get here, IAA is *REALLY* late. It's barely
* conceivable that the system is so busy that CMD_IAAD
* is still legitimately set, so let's be sure it's
* clear before we read STS_IAA. (The HC should clear
* CMD_IAAD when it sets STS_IAA.)
*/
cmd = ehci_readl(ehci, &ehci->regs->command);
/*
* If IAA is set here it either legitimately triggered
* after the watchdog timer expired (_way_ late, so we'll
* still count it as lost) ... or a silicon erratum:
* - VIA seems to set IAA without triggering the IRQ;
* - IAAD potentially cleared without setting IAA.
*/
status = ehci_readl(ehci, &ehci->regs->status);
if ((status & STS_IAA) || !(cmd & CMD_IAAD)) {
COUNT(ehci->stats.lost_iaa);
ehci_writel(ehci, STS_IAA, &ehci->regs->status);
}
ehci_vdbg(ehci, "IAA watchdog: status %x cmd %x\n",
status, cmd);
end_unlink_async(ehci);
/*
* If IAA is set here it either legitimately triggered
* after the watchdog timer expired (_way_ late, so we'll
* still count it as lost) ... or a silicon erratum:
* - VIA seems to set IAA without triggering the IRQ;
* - IAAD potentially cleared without setting IAA.
*/
status = ehci_readl(ehci, &ehci->regs->status);
if ((status & STS_IAA) || !(cmd & CMD_IAAD)) {
COUNT(ehci->stats.lost_iaa);
ehci_writel(ehci, STS_IAA, &ehci->regs->status);
}
ehci_dbg(ehci, "IAA watchdog: status %x cmd %x\n", status, cmd);
end_unlink_async(ehci);
}