Re: [RFC] usb: dwc2: hcd: fix split schedule issue

[Doug Anderson <dianders@chromium.org>]

John,

On Fri, Nov 6, 2015 at 2:04 AM, Yunzhi Li <lyz@rock-chips.com> wrote:
> hi John ,
>
>   As we talked yesterday, I tried to fix the split schedule sequence. This
> patch will
> avoid scheduling SSPLIT-IN packet for another device between
> SSPLIT-OUT-begin and
> SSPLIT-OUT-end, now the keyboard and Jebra audio speaker could work together
> well, but
> I'm not sure if this is exactly the right way to schedule split transfers
> and if there
> is any dide effect with this patch. Please help review this patch. Thanks.
>
>> Fix dwc2 split schedule sequence issue. Not schedule a SSPLIT_IN
>> packet between SSPLIT-begin and SSPLIT-end.
>>
>> Signed-off-by: Yunzhi Li <lyz@rock-chips.com>
>> ---
>>   drivers/usb/dwc2/hcd.c | 4 ++++
>>   1 file changed, 4 insertions(+)

Did you have any thoughts on this patch?  Although this patch didn't
fix the problems I was seeing with the Microsoft Wireless Keyboard
(see the patch I sent out earlier which does seem to fix it), I can
confirm that in a different setup (HUB goes to USB audio + mouse) that
this patch does fix some problems.

That being said, it feels to me like a band-aid rather than an actual
fix (I'm talking out of my rear end, though, since my USB experience
is lacking at best).  It feels like perhaps we're just not keeping
track the xact_pos correctly, but of course I don't know that for
sure...

Anyway, just fishing...  ;)

-Doug