[U-Boot] ehci-hcd: Allow cleanups to happen on an EHCI timeout.

[Joel A Fernandes]

Hi Simon,

Sorry for the delayed response to your email. I was just trying to
prepare a proper response to your email with collating information
about similar fixes to the EHCI timeout but never got to completing
it. Please excuse me, thanks.

I'm following up on your feedback for the patch titled:
ehci-hcd: Allow cleanups to happen on an EHCI timeout. [1]

> On Sat, Jun 25, 2011 at 12:28 PM, Joel A Fernandes <agnel.joel at gmail.com> wrote:
>> With this, the EHCI seems to "recover" from a timeout. This is particularly
>> observable if you were to ping the wrong IP Address and then ping the correct
>> one or if there was a temporary failure during tftp sessions.
>>
>> All it takes is one timeout to disable it. If you have a noisy network (lot
>> of traffic), even if the traffic is not for the board, the timeouts don't occur.
>>
>> Signed-off-by: Joel A Fernandes <agnel.joel at gmail.com>
>> ---
>> Robert, Could you see if this patch solves the issue you're seeing without
>> increasing the timeout?
>> Simon, Could this be a fix for a similar issue you were seeing with asix?
>
> Yes this is better (ASIX can recover from a timeout), but I am
> concerned that it carries on without reporting an error. Is that
> right?
>
> Should we disable async schedule and then return an error?

Actually, with this patch, the error message is still displayed before
disabling async schedule.

>
> With respect to using a bulk USB stick (some of which take 3s or more
> to respond to a submit) this doesn't make any difference for me. It
> seems to take a long time to respond the first time, so the 5s timeout
> seems prudent.
>
> Since this sorts out the network side we can probably skip that patch.
>

Are you suggesting we revert the patch you had submitted [2], instead
of deleting the goto line as done in my patch? I think it would be
better if we left [2] in and allowed the async disable to happen after
a timeout.

There are other patches that are reported to fix the issue such as [3]
and [4], but I think they appear to be more like workarounds and delay
the occurrence of the event of a timeout itself. A timeout which would
occur for any other reason such as too many USB devices connected to
the hub can trigger the problem, and, not running async schedule and
the other code after the timeout seems to make EHCI unrecoverable.

Looking forward to your suggestions, Thanks,

-Joel

[1] http://patchwork.ozlabs.org/patch/102041/
[2] http://lists.denx.de/pipermail/u-boot/2011-February/087043.html
[3] http://patchwork.ozlabs.org/patch/100367/
[4] https://github.com/kylemanna/u-boot/commit/a2211d841b5c5b67e1f336a7d8d1e6580a500cfb