On 16.04.2018 13:20, Tushar Nimkar wrote:
On 2018-04-05 11:31, Felipe Balbi wrote:
Hi,

it would help if you would Cc XHCI's maintainer :-)

tnim...@codeaurora.org writes:

On 2018-04-04 19:28, Greg KH wrote:
On Wed, Apr 04, 2018 at 06:41:41PM +0530, tnim...@codeaurora.org wrote:
On 2018-04-04 18:07, Greg KH wrote:
> On Wed, Apr 04, 2018 at 05:14:50PM +0530, tnim...@codeaurora.org wrote:
> > Hi Oliver/Greg,
> >
> > I am able to duplicated the UAS issue on 4.16 as well.
> > The behavior is same new usb device detects and reset after aprox 30
> > sec(SD_TIMEOUT)
> > Logs are already shared below.
> >
> > We are using Synopsys dwc3 as host controller, May I know have
> > tested it
> > with dwc3?
> > I have tried it on Linux PC (x86 Ubuntu machine) I could not see the
> > issue.
> > It enumerates well.
>
> Great, stick with an x86 platform!  :)
>
> Looks like a dwc3 host controller issue, try enabling tracing and
> debugging in that driver when this happens to see what is going on.

Oh if so let me enable the trace for that. I will respond you on this.

I did not get much clue, Greg.  sometime this device enumerates well,
attached both working and non working case logs.
following is not working case
root@OpenWrt:/# dmesg

...

[57214.172683] xhci-hcd xhci-hcd.0.auto: ep 0x83 - asked for 112 bytes,
96 bytes untransferred
[57214.172809] xhci-hcd xhci-hcd.0.auto: ep 0x83 - asked for 112 bytes,
96 bytes untransferred
[57214.172840] sd 1:0:0:0: [sdb] 976773168 512-byte logical blocks: (500
GB/466 GiB)
[57214.172843] xhci-hcd xhci-hcd.0.auto: ep 0x81 - asked for 4096 bytes,
4080 bytes untransferred
[57214.172851] xhci-hcd xhci-hcd.0.auto: ep 0x83 - asked for 112 bytes,
96 bytes untransferred
[57214.253085] xhci-hcd xhci-hcd.0.auto: xhci_hub_status_data: stopping
port polling.

Huge gap before uas_eh_abort_eh_handler is called.

[57246.701096] sd 1:0:0:0: tag#0 uas_eh_abort_handler 0 uas-tag 1
inflight: CMD IN
[57246.701130] sd 1:0:0:0: tag#0 CDB: opcode=0x1a 1a 00 3f 00 04 00

URB is canceled, maybe that URB never finished?

[57246.707583] xhci-hcd xhci-hcd.0.auto: Cancel URB 0000000007b523f0,
dev 1, ep 0x81, starting at offset 0
[57246.707594] xhci-hcd xhci-hcd.0.auto: // Ding dong!
[57246.707616] xhci-hcd xhci-hcd.0.auto: Stopped on No-op or Link TRB
for slot 1 ep 2
[57246.707625] xhci-hcd xhci-hcd.0.auto: Removing canceled TD starting
at 0x7f0cd0a0 (dma).
[57246.707630] xhci-hcd xhci-hcd.0.auto: Finding endpoint context
[57246.707634] xhci-hcd xhci-hcd.0.auto: Cycle state = 0x1
[57246.707637] xhci-hcd xhci-hcd.0.auto: New dequeue segment =
00000000890c7dc4 (virtual)
[57246.707641] xhci-hcd xhci-hcd.0.auto: New dequeue pointer =
0x7f0cd0b0 (DMA)
[57246.707646] xhci-hcd xhci-hcd.0.auto: Set TR Deq Ptr cmd, new deq seg
= 00000000890c7dc4 (0x7f0cd000 dmeq ptr = 000000000ce7faa0 (0x7f0cd0b0
dma), new cycle = 1
[57246.707651] xhci-hcd xhci-hcd.0.auto: // Ding dong!
[57246.707671] xhci-hcd xhci-hcd.0.auto: Successful Set TR Deq Ptr cmd,
deq = @7f0cd0b0
[57246.721090] scsi host1: uas_eh_device_reset_handler start
[57246.721114] xhci-hcd xhci-hcd.0.auto: Cancel URB 00000000279f06a2,
dev 1, ep 0x83, starting at offset 0
[57246.721120] xhci-hcd xhci-hcd.0.auto: // Ding dong!
[57246.721135] xhci-hcd xhci-hcd.0.auto: ERROR Transfer event for
unknown stream ring slot 1 ep 6
[57246.725463] xhci-hcd xhci-hcd.0.auto: @000000007f044780 00000000
00000000 1b000000 01078001

Stop -Length invalid transfer event. That is normal when canceling a URB,
but it should point to the TRB xhc was working on when stopped.
Here it just points to 0. That part looks like some issue with this specific
controller.

Some other errors may return 0 as their TRB pointer, but not this event.
But this is not the cause, just a detail while handling the real cause.
Nothing in this log shows why the URB was canceled in the first place.

usbmon and xhci traces could help, xhci traces:

mount -t debugfs none /sys/kernel/debug
echo 81920 > /sys/kernel/debug/tracing/buffer_size_kb
echo 1 > /sys/kernel/debug/tracing/events/xhci-hcd/enable

then send /sys/kernel/debug/tracing/trace after issue triggered.

-Mathias

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