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Re: [PATCH v6 18/22] usb: dwc2: host: Schedule periodic right away if it's time

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Kever,

On Mon, Feb 1, 2016 at 11:04 PM, Kever Yang <kever.yang@rock-chips.com> wrote:
>>> Oh, now I get what you're saying!
>>>
>>> A) You've got dwc2_release_channel() -> dwc2_deactivate_qh() ->
>>> dwc2_hcd_qh_deactivate()
>>> ...and always in that case we'll do a select / queue, so we don't need it
>>> there.
>>>
>>> B) You've got dwc2_hcd_urb_dequeue() -> dwc2_hcd_qh_deactivate()
>>>
>>> ...but why don't we need it for dwc2_hcd_urb_dequeue()?  Yes, you're
>>> not continuing a split so timing isn't quite as urgent, but you still
>>> might have an INT or ISOC packet that's scheduled with an interval of
>>> 1.  We still might want to schedule right away if there are remaining
>>> QTDs, right?
>>
>> I ran out of time to fully test today, but I couldn't actually get a
>> case where we needed to schedule right away for B).  ...so given your
>> point about the the select / queue already present in case A, we could
>> probably just drop this patch ("usb: dwc2: host: Schedule periodic
>> right away if it's time") and if we can find a case where it's needed
>> in case B we can add the select / queue there.
>>
>> Sound OK?  I'll try to do more testing tomorrow...
>
> Yes, we don't get a case we need to schedule right away for case B).
>
> For INT or ISOC packet, I can recall I have seen somewhere but I can find
> it now, the synchronous transfer is happen in the next uframe instead of the
> uframe
> when the host channel initialized, so there is no difference of setting the
> host channel register sooner or later inside the same frame.
> Which means the existent code should be OK for case A).
>
> We can drop this patch before we have the exact use case.

I put in some printouts and I finally did manage to find a place where
we needed to queue things up in dwc2_hcd_urb_dequeue().  I saw:

314.587916: QH=d9535340 next(0) fn=2a52, sch=2a51=>2a52 (+1) miss=0
314.588040: QH=d9535340 next(0) fn=2a53, sch=2a52=>2a53 (+1) miss=0
314.588162: QH=d9535340 next(0) fn=2a54, sch=2a53=>2a54 (+1) miss=0
314.588299: QH=d9535340 next(0) fn=2a55, sch=2a54=>2a55 (+1) miss=0
314.588304: QH=d9535340 queue in dwc2_hcd_urb_dequeue
314.588363: QH=d9535340 next(0) fn=2a55, sch=2a55=>2a56 (+1) miss=0
314.588413: dwc2_handle_hcd_intr: ff540000.usb: SCH: QH=e5cea380 ready
fn=2a56, nxt=2a56
314.588414: dwc2_handle_hcd_intr: ff540000.usb: SCH: QH=e73ccc40 ready
fn=2a56, nxt=2a56
314.588415: dwc2_handle_hcd_intr: ff540000.usb: SCH: QH=e5cea8c0 ready
fn=2a56, nxt=2a56

It's not something that's terribly common.  It's fine to just drop
this patch, or I can replace it with
<https://chromium-review.googlesource.com/325540>.

-Doug

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[PATCH v6 0/22] usb: dwc2: host: Fix and speed up all the stuff, especially with splits Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 09/22] usb: dwc2: host: Giveback URB in tasklet context Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 06/22] usb: dwc2: host: fix split transfer schedule sequence Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 15/22] usb: dwc2: host: Split code out to make dwc2_do_reserve() Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 22/22] usb: dwc2: host: If using uframe scheduler, end splits better Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 11/22] usb: dwc2: host: There's not really a TT for the root hub Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
    Re: [PATCH v6 11/22] usb: dwc2: host: There's not really a TT for  the root hub Kever Yang <kever.yang@rock-chips.com> - 2016-01-31 10:30 +0100
  [PATCH v6 02/22] usb: dwc2: host: Get aligned DMA in a more supported way Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 10/22] usb: dwc2: host: Properly set the HFIR Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
    Re: [PATCH v6 10/22] usb: dwc2: host: Properly set the HFIR Kever Yang <kever.yang@rock-chips.com> - 2016-01-31 10:30 +0100
      Re: [PATCH v6 10/22] usb: dwc2: host: Properly set the HFIR Doug Anderson <dianders@chromium.org> - 2016-01-31 23:20 +0100
  [PATCH v6 13/22] usb: dwc2: host: Rename some fields in struct dwc2_qh Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 04/22] usb: dwc2: host: Avoid use of chan->qh after qh freed Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 16/22] usb: dwc2: host: Add scheduler logging for missed SOFs Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 01/22] usb: dwc2: rockchip: Make the max_transfer_size automatic Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 17/22] usb: dwc2: host: Manage frame nums better in scheduler Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
    Re: [PATCH v6 17/22] usb: dwc2: host: Manage frame nums better in scheduler Doug Anderson <dianders@chromium.org> - 2016-02-03 21:40 +0100
  [PATCH v6 05/22] usb: dwc2: host: Always add to the tail of queues Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 19/22] usb: dwc2: host: Add dwc2_hcd_get_future_frame_number() call Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 03/22] usb: dwc2: host: Set host_rx_fifo_size to 525 for rk3066 Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 07/22] usb: dwc2: host: Add scheduler tracing Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 08/22] usb: dwc2: host: Add a delay before releasing periodic bandwidth Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 20/22] usb: dwc2: host: Properly set even/odd frame Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
    Re: [PATCH v6 20/22] usb: dwc2: host: Properly set even/odd frame Kever Yang <kever.yang@rock-chips.com> - 2016-02-02 08:50 +0100
      Re: [PATCH v6 20/22] usb: dwc2: host: Properly set even/odd frame Doug Anderson <dianders@chromium.org> - 2016-02-02 23:50 +0100
        Re: [PATCH v6 20/22] usb: dwc2: host: Properly set even/odd frame Kever Yang <kever.yang@rock-chips.com> - 2016-02-03 08:50 +0100
  [PATCH v6 18/22] usb: dwc2: host: Schedule periodic right away if it's time Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
    Re: [PATCH v6 18/22] usb: dwc2: host: Schedule periodic right away  if it's time Kever Yang <kever.yang@rock-chips.com> - 2016-01-31 10:40 +0100
      Re: [PATCH v6 18/22] usb: dwc2: host: Schedule periodic right away if  it's time Doug Anderson <dianders@chromium.org> - 2016-01-31 23:10 +0100
        Re: [PATCH v6 18/22] usb: dwc2: host: Schedule periodic right away  if it's time Kever Yang <kever.yang@rock-chips.com> - 2016-02-01 04:40 +0100
          Re: [PATCH v6 18/22] usb: dwc2: host: Schedule periodic right away if  it's time Doug Anderson <dianders@chromium.org> - 2016-02-01 05:40 +0100
            Re: [PATCH v6 18/22] usb: dwc2: host: Schedule periodic right away if  it's time Doug Anderson <dianders@chromium.org> - 2016-02-02 01:40 +0100
              Re: [PATCH v6 18/22] usb: dwc2: host: Schedule periodic right away  if it's time Kever Yang <kever.yang@rock-chips.com> - 2016-02-02 08:10 +0100
                Re: [PATCH v6 18/22] usb: dwc2: host: Schedule periodic right away if  it's time Doug Anderson <dianders@chromium.org> - 2016-02-03 00:40 +0100
  [PATCH v6 14/22] usb: dwc2: host: Reorder things in hcd_queue.c Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  [PATCH v6 12/22] usb: dwc2: host: Use periodic interrupt even with DMA Douglas Anderson <dianders@chromium.org> - 2016-01-29 03:30 +0100
  Re: [PATCH v6 0/22] usb: dwc2: host: Fix and speed up all the  stuff, especially with splits John Youn <John.Youn@synopsys.com> - 2016-02-03 01:00 +0100
    Re: [PATCH v6 0/22] usb: dwc2: host: Fix and speed up all the stuff,  especially with splits Doug Anderson <dianders@chromium.org> - 2016-02-03 19:30 +0100

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