On Fri, Jun 15, 2012 at 7:55 AM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> On Thu, 14 Jun 2012, Austin Schuh wrote:
>
>> > Here's something to try. In ehci-hcd.c:ehci_iaa_watchdog(), change the
>> > ehci_vdbg() function call to ehci_warn(), leaving the arguments the
>> > same. This will log a message for each of the lost IAA interrupts, so
>> > we'll be able to see a little bit of what's happening.
>>
>> Here's your dump. For completeness, I had ehci->need_io_watchdog = 1
>> enabled, on the desktop machine, kernel 2.6.38.8.
>> All the other entries look very similar to one of these two. I can
>> give you more of them if you would like.
>>
> Those are the important entries.
>
>> cat /var/log/syslog | IAA
>>
>> Jun 14 13:35:10 aschuh kernel: [ 407.168318] ehci_hcd 0000:00:1a.7:
>> IAA watchdog: status c028 cmd 10031
>> Jun 14 13:41:36 aschuh kernel: [ 792.939975] ehci_hcd 0000:00:1a.7:
>> IAA watchdog: status 8028 cmd 10021
>> Jun 14 13:41:54 aschuh kernel: [ 810.747858] ehci_hcd 0000:00:1a.7:
>> IAA watchdog: status c028 cmd 10031
>> Jun 14 13:45:40 aschuh kernel: [ 1036.705444] ehci_hcd 0000:00:1a.7:
>> IAA watchdog: status c028 cmd 10031
>> Jun 14 13:45:47 aschuh kernel: [ 1042.827822] ehci_hcd 0000:00:1a.7:
>> IAA watchdog: status c028 cmd 10031
>> Jun 14 13:52:09 aschuh kernel: [ 1424.787116] ehci_hcd 0000:00:1a.7:
>> IAA watchdog: status 8028 cmd 10021
>> Jun 14 13:56:10 aschuh kernel: [ 1665.323853] ehci_hcd 0000:00:1a.7:
>> IAA watchdog: status c028 cmd 10031
>> Jun 14 13:57:38 aschuh kernel: [ 1753.762315] ehci_hcd 0000:00:1a.7:
>> IAA watchdog: status 8028 cmd 10021
>> Jun 14 14:01:23 aschuh kernel: [ 1977.839189] ehci_hcd 0000:00:1a.7:
>> IAA watchdog: status c028 cmd 10031
>> Jun 14 14:04:01 aschuh kernel: [ 2135.979125] ehci_hcd 0000:00:1a.7:
>> IAA watchdog: status c028 cmd 10031
>> Jun 14 14:09:31 aschuh kernel: [ 2465.372666] ehci_hcd 0000:00:1a.7:
>> IAA watchdog: status 8028 cmd 10021
>> Jun 14 14:18:32 aschuh kernel: [ 3005.369987] ehci_hcd 0000:00:1a.7:
>> IAA watchdog: status e028 cmd 10031
>
> Those indicate that IRQs are getting lost. I have no idea why, except
> that it probably isn't a problem in the USB hardware. Maybe something
> is wrong with interrupt-handling hardware. On the other hand, a
> hardware problem is unlikely to affect multiple different computer
> systems.
>
> To confirm the diagnosis, apply the patch below along with your change
> to the iaa_watchdog routine. It'll generate a lot of output; only the
> entries that are close to the IAA watchdog messages will matter.
>
> Alan Stern
>
> Index: v/drivers/usb/host/ehci-hcd.c
> ===================================================================
> --- v.orig/drivers/usb/host/ehci-hcd.c
> +++ v/drivers/usb/host/ehci-hcd.c
> @@ -851,6 +851,8 @@ static irqreturn_t ehci_irq (struct usb_
> spin_lock (&ehci->lock);
>
> status = ehci_readl(ehci, &ehci->regs->status);
> + ehci_info(ehci, "IRQ: status %x cmd %x\n", status,
> + ehci_readl(ehci, &ehci->regs->command));
>
> /* e.g. cardbus physical eject */
> if (status == ~(u32) 0) {
>
Here's another dump. Same machine, same kernel.a
[ 328.346687] ehci_hcd 0000:00:1a.7: IRQ: status 8009 cmd 10021
[ 328.346771] ehci_hcd 0000:00:1a.7: IAA watchdog: status 8028 cmd 10021
[ 328.346780] ehci_hcd 0000:00:1a.7: IRQ: status 8008 cmd 10021
[ 1007.149450] ehci_hcd 0000:00:1a.7: IRQ: status c009 cmd 10031
[ 1007.149493] ehci_hcd 0000:00:1a.7: IAA watchdog: status c028 cmd 10031
[ 1007.149821] ehci_hcd 0000:00:1a.7: IRQ: status c009 cmd 10031
[ 1150.328479] ehci_hcd 0000:00:1a.7: IRQ: status 8009 cmd 10021
[ 1150.328551] ehci_hcd 0000:00:1a.7: IAA watchdog: status 8028 cmd 10021
[ 1150.329227] ehci_hcd 0000:00:1a.7: IRQ: status 8009 cmd 10021
[ 1150.329309] ehci_hcd 0000:00:1a.7: IRQ: status 8028 cmd 10021
[ 1216.624651] ehci_hcd 0000:00:1a.7: IRQ: status c009 cmd 10031
[ 1216.624716] ehci_hcd 0000:00:1a.7: IAA watchdog: status c028 cmd 10031
[ 1216.634720] ehci_hcd 0000:00:1a.7: IRQ: status c028 cmd 10031
[ 1294.496102] ehci_hcd 0000:00:1a.7: IRQ: status c009 cmd 10031
[ 1294.496211] ehci_hcd 0000:00:1a.7: IAA watchdog: status c028 cmd 10031
[ 1294.496515] ehci_hcd 0000:00:1a.7: IRQ: status c009 cmd 10031
[ 1356.078251] ehci_hcd 0000:00:1a.7: IRQ: status c009 cmd 10031
[ 1356.078294] ehci_hcd 0000:00:1a.7: IAA watchdog: status c028 cmd 10031
[ 1356.078556] ehci_hcd 0000:00:1a.7: IRQ: status c009 cmd 10031
Austin Schuh
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