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Subject: Re: [PATCH v10 0/6] Re-introduce TX FIFO resize for larger EP
 bursting
To:     Ferry Toth <fntoth@gmail.com>, Felipe Balbi <balbi@kernel.org>
Cc:     Wesley Cheng <wcheng@codeaurora.org>, gregkh@linuxfoundation.org,
        robh+dt@kernel.org, agross@kernel.org, bjorn.andersson@linaro.org,
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        linux-arm-msm@vger.kernel.org, jackp@codeaurora.org,
        heikki.krogerus@linux.intel.com, andy.shevchenko@gmail.com,
        Ruslan Bilovol <ruslan.bilovol@gmail.com>
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From:   Pavel Hofman <pavel.hofman@ivitera.com>
Message-ID: <d298df65-417b-f318-9374-b463a15d8308@ivitera.com>
Date:   Thu, 19 Aug 2021 09:51:09 +0200
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Hi,

Dne 18. 08. 21 v 21:07 Ferry Toth napsal(a):
> Hi,
> 
> Op 18-08-2021 om 00:00 schreef Ferry Toth:
>> Hi,
>>
>> Op 16-08-2021 om 07:18 schreef Felipe Balbi:
>>> Hi,
>>>
>>> Ferry Toth <fntoth@gmail.com> writes:
>>>>> Ferry Toth <fntoth@gmail.com> writes:
>>>>>>>>> Ferry Toth <fntoth@gmail.com> writes:
>>>>>>>>>>>>>> Hardware name: Intel Corporation Merrifield/BODEGA BAY, 
>>>>>>>>>>>>>> BIOS 542
>>>>>>>>>>>>>> 2015.01.21:18.19.48
>>>>>>>>>>>>>> RIP: 0010:0x500000000
>>>>>>>>>>>>>> Code: Unable to access opcode bytes at RIP 0x4ffffffd6.
>>>>>>>>>>>>>> RSP: 0018:ffffa4d00045fc28 EFLAGS: 00010046
>>>>>>>>>>>>>> RAX: 0000000500000000 RBX: ffff8cd546aed200 RCX: 
>>>>>>>>>>>>>> 0000000000000000
>>>>>>>>>>>>>> RDX: 0000000000000000 RSI: ffff8cd547bfcae0 RDI: 
>>>>>>>>>>>>>> ffff8cd546aed200
>>>>>>>>>>>>>> RBP: ffff8cd547bfcae0 R08: 0000000000000000 R09: 
>>>>>>>>>>>>>> 0000000000000001
>>>>>>>>>>>>>> R10: ffff8cd541fd28c0 R11: 0000000000000000 R12: 
>>>>>>>>>>>>>> ffff8cd547342828
>>>>>>>>>>>>>> R13: ffff8cd546aed248 R14: 0000000000000000 R15: 
>>>>>>>>>>>>>> ffff8cd548b1d000
>>>>>>>>>>>>>> FS:  0000000000000000(0000) GS:ffff8cd57e200000(0000) 
>>>>>>>>>>>>>> knlGS:0000000000000000
>>>>>>>>>>>>>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>>>>>>>>>>>> CR2: 0000000500000000 CR3: 000000000311e000 CR4: 
>>>>>>>>>>>>>> 00000000001006f0
>>>>>>>>>>>>>> Call Trace:
>>>>>>>>>>>>>>         ? dwc3_remove_requests.constprop.0+0x14d/0x170
>>>>>>>>>>>>>>         ? __dwc3_gadget_ep_disable+0x7a/0x160
>>>>>>>>>>>>>>         ? dwc3_gadget_ep_disable+0x3d/0xd0
>>>>>>>>>>>>>>         ? usb_ep_disable+0x1c/0x
>>>>>>>>>>>>>>         ? u_audio_stop_capture+0x79/0x120 [u_audio]
>>>>>>>>>>>>>>         ? afunc_set_alt+0x73/0x80 [usb_f_uac2]
>>>>>>> So this is triggered by a SetInterface request...
>>>>>>>
>>>>>>>>>>>>>>         ? composite_setup+0x224/0x1b90 [libcomposite]
>>>>>>>>>>>>>>         ? __dwc3_gadget_kick_transfer+0x160/0x400
>>>>>>>>>>>>>>         ? dwc3_gadget_ep_queue+0xf3/0x1a0
>>>>>>>>>>>>>>         ? configfs_composite_setup+0x6b/0x90 [libcomposite]
>>>>>>>>>>>>>>         ? configfs_composite_setup+0x6b/0x90 [libcomposite]
>>>>>>>>>>>>>>         ? dwc3_ep0_interrupt+0x459/0xa40
>>>>>>>>>>>>>>         ? dwc3_thread_interrupt+0x8ee/0xf40
>>>>>>>>>>>>>>         ? __schedule+0x235/0x6c0
>>>>>>>>>>>>>>         ? disable_irq_nosync+0x10/0x10
>>>>>>>>>>>>>>         ? irq_thread_fn+0x1b/0x60
>>>>>>>>>>>>>>         ? irq_thread+0xc0/0x160
>>>>>>>>>>>>>>         ? irq_thread_check_affinity+0x70/0x70
>>>>>>>>>>>>>>         ? irq_forced_thread_fn+0x70/0x70
>>>>>>>>>>>>>>         ? kthread+0x122/0x140
>>>>>>>>>>>>>>         ? set_kthread_struct+0x40/0x40
>>>>>>>>>>>>>>         ? ret_from_fork+0x22/0x30
>>>>>>>>>>>>> Do you mind enabling dwc3 traces and collecting them? 
>>>>>>>>>>>>> Trying to figure
>>>>>>>>>>>>> out how we got here.
>>>>>>>>>>>>>
>>>>>>>>>>>> I'll try if I can get the same error by booting with USB in 
>>>>>>>>>>>> host mode
>>>>>>>>>>>> and then switch to device mode. If so I can enable traces 
>>>>>>>>>>>> and collect as
>>>>>>>>>>>> you explained me before.
>>>>>>>>>>>>
>>>>>>>>>>>> I'll try before monday, as then I fly for a holiday and will 
>>>>>>>>>>>> not be
>>>>>>>>>>>> available before rc5.
>>>>>>>>>>> you can enable all of those with kernel cmdline :-)
>>>>>>>>>>>
>>>>>>>>>>> https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html 
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> you need ftrace_dump_on_oops=1 and also need the correct 
>>>>>>>>>>> options on
>>>>>>>>>>> trace_buf_size and trace_event.
>>>>>>>>>>>
>>>>>>>>>> On Edison-Arduino I have a switch to go to device mode, after 
>>>>>>>>>> which
>>>>>>>>>> udev triggers a script configure gadgets through configfs.
>>>>>>>>>>
>>>>>>>>>> I tried to log following these instructions:
>>>>>>>>>>
>>>>>>>>>> https://www.kernel.org/doc/html/latest/driver-api/usb/dwc3.html#reporting-bugs 
>>>>>>>>>> <https://www.kernel.org/doc/html/latest/driver-api/usb/dwc3.html#reporting-bugs> 
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Unfortunately the kernel crashes so badly I can not get to the 
>>>>>>>>>> ` cp
>>>>>>>>>> /t/trace /root/trace.txt` line (after a while the watchdog 
>>>>>>>>>> kicks).
>>>>>>>>>>
>>>>>>>>>> What to do next?
>>>>>>>>> Pass ftrace_dump_on_oops to kernel cmdline.
>>>>>>>>>
>>>>>>>> No sure if I did this right, on oops everything is pushed to 
>>>>>>>> console
>>>>>>>> (115k2 serial), I hope nothing essential is lost.
>>>>>>>>
>>>>>>>> I copied the screen buffer to file see attached.
>>>>>>> Thank you, I bet it took quite a some time :-) Anyway, looking at
>>>>>>> the logs around Set Interface requests, we can track every endpoint
>>>>>>> that's disabled. I'll take a guess and assume we're failing at 
>>>>>>> the last
>>>>>>> Set Interface, that means we should have something odd with 
>>>>>>> ep6in, but
>>>>>>> everything looks fine in the trace output:
>>>>>>>
>>>>>>> [   75.823107] irq/14-d-596       0d... 42789194us : 
>>>>>>> dwc3_gadget_ep_enable: ep6in: mps 192/346 streams 16 burst 0 ring 
>>>>>>> 0/0 flags E:swbp:<
>>>>>>> [   75.835472] irq/14-d-596       0d... 42789198us : 
>>>>>>> dwc3_alloc_request: ep6in: req 0000000002c71409 length 0/0 zsI ==> 0
>>>>>>> [   75.846416] irq/14-d-596       0d... 42789202us : 
>>>>>>> dwc3_ep_queue: ep6in: req 0000000002c71409 length 0/192 zsI ==> -115
>>>>>>> [   75.857360] irq/14-d-596       0d... 42789204us : 
>>>>>>> dwc3_alloc_request: ep6in: req 00000000a324f5d0 length 0/0 zsI ==> 0
>>>>>>> [   75.868301] irq/14-d-596       0d... 42789206us : 
>>>>>>> dwc3_ep_queue: ep6in: req 00000000a324f5d0 length 0/192 zsI ==> -115
>>>>>>> [   75.879244] irq/14-d-596       0d... 42789209us : dwc3_event: 
>>>>>>> event (000020c2): ep0in: Transfer Not Ready [0] (Not Active) 
>>>>>>> [Status Phase]
>>>>>>> [   75.891880] irq/14-d-596       0d... 42789211us : 
>>>>>>> dwc3_prepare_trb: ep0in: trb 000000004c0ae319 (E0:D0) buf 
>>>>>>> 000000001bded000 size 0 ctrl 00000c33 (HLcs:SC:status2)
>>>>>>> [   75.989131] irq/14-d-596       0d... 42789224us : 
>>>>>>> dwc3_gadget_ep_cmd: ep0in: cmd 'Start Transfer' [406] params 
>>>>>>> 00000000 1bded000 00000000 --> status: Successful
>>>>>>> [   76.096261] irq/14-d-596       0d... 42789272us : dwc3_event: 
>>>>>>> event (0000c042): ep0in: Transfer Complete (sIL) [Status Phase]
>>>>>>> [   76.107834] irq/14-d-596       0d... 42789275us : 
>>>>>>> dwc3_complete_trb: ep0out: trb 000000004c0ae319 (E0:D0) buf 
>>>>>>> 000000001bded000 size 0 ctrl 00000c32 (hLcs:SC:status2)
>>>>>>> [   76.122944] irq/14-d-596       0d... 42789277us : 
>>>>>>> dwc3_gadget_giveback: ep0out: req 00000000cb1bd3cd length 0/0 zsI 
>>>>>>> ==> 0
>>>>>>> [   76.134160] irq/14-d-596       0d... 42789280us : 
>>>>>>> dwc3_prepare_trb: ep0out: trb 000000004c0ae319 (E0:D0) buf 
>>>>>>> 000000001bded000 size 8 ctrl 00000c23 (HLcs:SC:setup)
>>>>>>> [   76.231322] irq/14-d-596       0d... 42789292us : 
>>>>>>> dwc3_gadget_ep_cmd: ep0out: cmd 'Start Transfer' [406] params 
>>>>>>> 00000000 1bded000 00000000 --> status: Successful
>>>>>>> [   76.297418] kworker/-23        0d... 42789670us : 
>>>>>>> dwc3_ep_queue: ep3in: req 0000000029586135 length 0/96 ZsI ==> -115
>>>>>>> [   76.308278] kworker/-23        0d... 42789695us : 
>>>>>>> dwc3_prepare_trb: ep3in: trb 00000000b81213d6 (E1:D0) buf 
>>>>>>> 0000000003b7a800 size 96 ctrl 00000811 (Hlcs:sC:normal)
>>>>>>> [   76.395294] kworker/-23        0d... 42789707us : 
>>>>>>> dwc3_gadget_ep_cmd: ep3in: cmd 'Update Transfer' [60007] params 
>>>>>>> 00000000 00000000 00000000 --> status: Successful
>>>>>>> [   76.471900] irq/14-d-596       0d... 42789842us : dwc3_event: 
>>>>>>> event (0000c040): ep0out: Transfer Complete (sIL) [Setup Phase]
>>>>>>> [   76.489308] irq/14-d-596       0d... 42789845us : 
>>>>>>> dwc3_ctrl_req: Set Interface(Intf = 5, Alt.Setting = 0)
>>>>>>> [   76.505650] irq/14-d-596       0d... 42789851us : 
>>>>>>> dwc3_ep_dequeue: ep6in: req 0000000002c71409 length 0/192 zsI ==> 
>>>>>>> -115
>>>>>>> [   76.523315] irq/14-d-596       0d... 42789854us : 
>>>>>>> dwc3_gadget_giveback: ep6in: req 0000000002c71409 length 0/192 
>>>>>>> zsI ==> -104
>>>>>>> [   76.541427] irq/14-d-596       0d... 42789857us : 
>>>>>>> dwc3_free_request: ep6in: req 0000000002c71409 length 0/192 zsI 
>>>>>>> ==> -104
>>>>>>> [   76.559267] irq/14-d-596       0d... 42789859us : 
>>>>>>> dwc3_ep_dequeue: ep6in: req 00000000a324f5d0 length 0/192 zsI ==> 
>>>>>>> -115
>>>>>>> [   76.576937] irq/14-d-596       0d... 42789861us : 
>>>>>>> dwc3_gadget_giveback: ep6in: req 00000000a324f5d0 length 0/192 
>>>>>>> zsI ==> -104
>>>>>>> [   76.595046] irq/14-d-596       0d... 42789862us : 
>>>>>>> dwc3_free_request: ep6in: req 00000000a324f5d0 length 0/192 zsI 
>>>>>>> ==> -104
>>>>>>> [   76.612892] irq/14-d-596       0d... 42789865us : 
>>>>>>> dwc3_gadget_ep_disable: ep6in: mps 192/346 streams 16 burst 0 
>>>>>>> ring 0/0 flags E:swbp:<
>>>>>>> [   76.665535] irq/14-d-596       0d... 42789873us : dwc3_event: 
>>>>>>> event (000020c2): ep0in: Transfer Not Ready [0] (Not Active) 
>>>>>>> [Status Phase]
>>>>>>> [   76.684716] irq/14-d-596       0d... 42789875us : 
>>>>>>> dwc3_prepare_trb: ep0in: trb 000000004c0ae319 (E0:D0) buf 
>>>>>>> 000000001bded000 size 0 ctrl 00000c33 (HLcs:SC:status2)
>>>>>>> [   76.819195] irq/14-d-596       0d... 42789886us : 
>>>>>>> dwc3_gadget_ep_cmd: ep0in: cmd 'Start Transfer' [406] params 
>>>>>>> 00000000 1bded000 00000000 --> status: Successful
>>>>>>> [   76.926324] irq/14-d-596       0d... 42789930us : dwc3_event: 
>>>>>>> event (0000c042): ep0in: Transfer Complete (sIL) [Status Phase]
>>>>>>> [   76.937892] irq/14-d-596       0d... 42789933us : 
>>>>>>> dwc3_complete_trb: ep0out: trb 000000004c0ae319 (E0:D0) buf 
>>>>>>> 000000001bded000 size 0 ctrl 00000c32 (hLcs:SC:status2)
>>>>>>> [   76.953003] irq/14-d-596       0d... 42789935us : 
>>>>>>> dwc3_gadget_giveback: ep0out: req 00000000cb1bd3cd length 0/0 zsI 
>>>>>>> ==> 0
>>>>>>> [   76.964217] irq/14-d-596       0d... 42789938us : 
>>>>>>> dwc3_prepare_trb: ep0out: trb 000000004c0ae319 (E0:D0) buf 
>>>>>>> 000000001bded000 size 8 ctrl 00000c23 (HLcs:SC:setup)
>>>>>>> [   77.061379] irq/14-d-596       0d... 42789950us : 
>>>>>>> dwc3_gadget_ep_cmd: ep0out: cmd 'Start Transfer' [406] params 
>>>>>>> 00000000 1bded000 00000000 --> status: Successful
>>>>>>> [   77.168595] irq/14-d-596       0d... 42790509us : dwc3_event: 
>>>>>>> event (0000c040): ep0out: Transfer Complete (sIL) [Setup Phase]
>>>>>>> [   77.180159] irq/14-d-596       0d... 42790512us : 
>>>>>>> dwc3_ctrl_req: Get String Descriptor(Index = 18, Length = 255)
>>>>>>> [   77.190578] irq/14-d-596       0d... 42790537us : 
>>>>>>> dwc3_prepare_trb: ep0in: trb 000000004c0ae319 (E0:D0) buf 
>>>>>>> 0000000003b68000 size 36 ctrl 00000c53 (HLcs:SC:data)
>>>>>>> [   77.287648] irq/14-d-596       0d... 42790550us : 
>>>>>>> dwc3_gadget_ep_cmd: ep0in: cmd 'Start Transfer' [406] params 
>>>>>>> 00000000 1bded000 00000000 --> status: Successful
>>>>>>> [   77.333107] irq/14-d-596       0d... 42790557us : dwc3_event: 
>>>>>>> event (000010c2): ep0in: Transfer Not Ready [0] (Not Active) 
>>>>>>> [Data Phase]
>>>>>>> [   77.407223] irq/14-d-596       0d... 42790575us : dwc3_event: 
>>>>>>> event (000090c2): ep0in: Transfer Not Ready [0] (Active) [Data 
>>>>>>> Phase]
>>>>>>> [   77.480985] irq/14-d-596       0d... 42790588us : dwc3_event: 
>>>>>>> event (0000c042): ep0in: Transfer Complete (sIL) [Data Phase]
>>>>>>> [   77.492376] irq/14-d-596       0d... 42790590us : 
>>>>>>> dwc3_complete_trb: ep0out: trb 000000004c0ae319 (E0:D0) buf 
>>>>>>> 0000000003b68000 size 0 ctrl 00000c52 (hLcs:SC:data)
>>>>>>> [   77.507221] irq/14-d-596       0d... 42790595us : 
>>>>>>> dwc3_gadget_giveback: ep0out: req 00000000cb1bd3cd length 36/36 
>>>>>>> ZsI ==> 0
>>>>>>> [   77.518609] irq/14-d-596       0d... 42790597us : dwc3_event: 
>>>>>>> event (000020c0): ep0out: Transfer Not Ready [0] (Not Active) 
>>>>>>> [Status Phase]
>>>>>>> [   77.531332] irq/14-d-596       0d... 42790598us : 
>>>>>>> dwc3_prepare_trb: ep0out: trb 000000004c0ae319 (E0:D0) buf 
>>>>>>> 000000001bded000 size 0 ctrl 00000c43 (HLcs:SC:status3)
>>>>>>> [   77.628669] irq/14-d-596       0d... 42790609us : 
>>>>>>> dwc3_gadget_ep_cmd: ep0out: cmd 'Start Transfer' [406] params 
>>>>>>> 00000000 1bded000 00000000 --> status: Successful
>>>>>>>
>>>>>>> Do you mind adding a few prints in dwc3_remove_requests to tell 
>>>>>>> us which
>>>>>>> endpoint is being processed? Then we'll know for sure which one 
>>>>>>> caused
>>>>>>> the crash.
>>>>>>>
>>>>>> I wouldn't mind but am leaving on a holiday, won't have time until 
>>>>>> 6 aug.
>>>>> not a problem, we'll still be here when you're back :-)
>>>> Well, let's go then :-)
>>>>
>>>> To get back in the mood I have retested 5.13.0, 5.14.0-rc1, 5.14.0-rc2
>>>> and 5.14.0-rc5.
>>>>
>>>> I find that 5.13.0 works fine, and the issue starts from 5.14.0-rc1.
>>> That's great finding. We have a bisection point. There are a total of
>>> 13764 commits between v5.13 and v5.14-rc1
>>>
>>>     $ git rev-list  --count v5.13..v5.14-rc1
>>>     13764
>>>
>>> git bisect should find the offending commit in at most 14 tries. That's
>>> not too bad.
>> I correctly guesstimated that the problem got introduced by the usb 
>> merge 79160a60
>>
>> "Merge tag 'usb-5.14-rc1' of 
>> git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb"
>>
>> 116 commits(7 bisects).
>>
>> 24f779dac8f3efb9629adc0e486914d93dc45517 is the first bad commit
>>
>> "usb: gadget: f_uac2/u_audio: add feedback endpoint support"
>>
>> Ruslan's 3 patches are related to each other so I reverted all three 
>> 24f779da...e89bb428 and applied the reverts to rc1.
>>
>> I can confirm this indeed resolves the problem in rc1.
>>
>> Is late now, tomorrow evening I will apply the reverts to rc6.
> 
> With these reverts rc6 works fine as well.
> 
> So, where do we go from here?
> 

I know the patches have been tested on dwc2 (by me and others).  I do 
not know if Ruslan or Jerome tested them on dwc3 but probably not. 
Ruslan has talked about RPi (my case too) and BeagleboneBlack, both with 
dwc2. Perhaps the dwc2 behaves a bit differently than dwc3?

The patches add a new EP-IN for async feedback. I am sorry I have not 
followed your long thread (it started as unrelated to uac). Does the 
problem appear with f_uac1 or f_uac2? Please how have you reached the 
above problem?

u_audio_stop_capture calls free_ep_fback 
https://elixir.bootlin.com/linux/v5.14-rc6/source/drivers/usb/gadget/function/u_audio.c#L414 
which clears the feedback request prm->req_fback.

Then (reading from your the call trace), usb_ep_disable calls 
dwc3_gadget_ep_disable which for every request in the EP calls 
dwc3_remove_requests which gives every found request back to the gadget 
function, IIUC by calling the complete method of the request 
https://elixir.bootlin.com/linux/v5.14-rc6/source/drivers/usb/gadget/udc/core.c#L912 
. Perhaps the problem is somewhere here?

The dwc2 gadget has its endpoint_disable method a bit different 
https://elixir.bootlin.com/linux/v5.14-rc6/source/drivers/usb/dwc2/gadget.c#L4200 
  -> 
https://elixir.bootlin.com/linux/v5.14-rc6/source/drivers/usb/dwc2/gadget.c#L3251 
-> 
https://elixir.bootlin.com/linux/v5.14-rc6/source/drivers/usb/dwc2/gadget.c#L2090 
which also calls usb_gadget_giveback_request 
https://elixir.bootlin.com/linux/v5.14-rc6/source/drivers/usb/dwc2/gadget.c#L2126 
. Perhaps there is some minor but important difference in processing the 
requests when disabling the endpoint between dwc2 and dwc3?

Thanks,

Pavel.