From: Felipe Balbi <balbi@kernel.org>
To: John Stultz <john.stultz@linaro.org>,
lkml <linux-kernel@vger.kernel.org>
Cc: Anurag Kumar Vulisha <anurag.kumar.vulisha@xilinx.com>,
Yang Fei <fei.yang@intel.com>, Thinh Nguyen <thinhn@synopsys.com>,
Tejas Joglekar <tejas.joglekar@synopsys.com>,
Andrzej Pietrasiewicz <andrzej.p@collabora.com>,
Jack Pham <jackp@codeaurora.org>, Todd Kjos <tkjos@google.com>,
Greg KH <gregkh@linuxfoundation.org>,
Linux USB List <linux-usb@vger.kernel.org>,
stable <stable@vger.kernel.org>,
John Stultz <john.stultz@linaro.org>
Subject: Re: [RFC][PATCH 1/2] usb: dwc3: gadget: Check for IOC/LST bit in both event->status and TRB->ctrl fields
Date: Thu, 23 Jan 2020 09:24:17 +0200 [thread overview]
Message-ID: <87tv4m4ov2.fsf@kernel.org> (raw)
In-Reply-To: <20200122222645.38805-2-john.stultz@linaro.org>
[-- Attachment #1: Type: text/plain, Size: 1495 bytes --]
Hi,
John Stultz <john.stultz@linaro.org> writes:
> From: Anurag Kumar Vulisha <anurag.kumar.vulisha@xilinx.com>
>
> The present code in dwc3_gadget_ep_reclaim_completed_trb() will check
> for IOC/LST bit in the event->status and returns if IOC/LST bit is
> set. This logic doesn't work if multiple TRBs are queued per
> request and the IOC/LST bit is set on the last TRB of that request.
> Consider an example where a queued request has multiple queued TRBs
> and IOC/LST bit is set only for the last TRB. In this case, the Core
> generates XferComplete/XferInProgress events only for the last TRB
> (since IOC/LST are set only for the last TRB). As per the logic in
> dwc3_gadget_ep_reclaim_completed_trb() event->status is checked for
> IOC/LST bit and returns on the first TRB. This makes the remaining
> TRBs left unhandled.
> To aviod this, changed the code to check for IOC/LST bits in both
avoid
> event->status & TRB->ctrl. This patch does the same.
We don't need to check both. It's very likely that checking the TRB is
enough.
> At a practical level, this patch resolves USB transfer stalls seen
> with adb on dwc3 based HiKey960 after functionfs gadget added
> scatter-gather support around v4.20.
Right, I remember asking for tracepoint data showing this problem
happening. It's the best way to figure out what's really going on.
Before we accept these two patches, could you collect dwc3 tracepoint
data and share here?
--
balbi
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 832 bytes --]
next prev parent reply other threads:[~2020-01-23 7:23 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-22 22:26 [RFC][PATCH 0/2] Avoiding DWC3 transfer stalls/hangs when using adb over f_fs John Stultz
2020-01-22 22:26 ` [RFC][PATCH 1/2] usb: dwc3: gadget: Check for IOC/LST bit in both event->status and TRB->ctrl fields John Stultz
2020-01-23 7:24 ` Felipe Balbi [this message]
2020-01-23 18:54 ` Yang, Fei
[not found] ` <CALAqxLUeBf2Jx2tLW1yzJk6JHM0RP9cJbTt7m19Qdz-rWMw2mQ@mail.gmail.com>
2020-01-24 7:45 ` Felipe Balbi
2020-01-24 22:10 ` John Stultz
2020-01-25 11:02 ` Felipe Balbi
2020-01-27 18:48 ` John Stultz
2020-01-22 22:26 ` [RFC][PATCH 2/2] usb: dwc3: gadget: Correct the logic for finding last SG entry John Stultz
2020-01-23 7:25 ` Felipe Balbi
2020-01-23 15:50 ` Anurag Kumar Vulisha
2020-01-23 7:18 ` [RFC][PATCH 0/2] Avoiding DWC3 transfer stalls/hangs when using adb over f_fs Felipe Balbi
2020-01-23 8:43 ` Andrzej Pietrasiewicz
2020-01-23 16:29 ` Yang, Fei
2020-01-23 17:31 ` Felipe Balbi
2020-01-23 17:37 ` Yang, Fei
2020-01-23 17:46 ` Felipe Balbi
2020-01-23 18:28 ` Yang, Fei
2020-02-05 21:03 ` John Stultz
2020-02-06 6:23 ` Felipe Balbi
2020-02-06 7:40 ` Christoph Hellwig
2020-02-06 18:29 ` Felipe Balbi
2020-02-06 18:41 ` Christoph Hellwig
2020-02-07 6:00 ` Felipe Balbi
2020-01-23 19:58 ` John Stultz
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87tv4m4ov2.fsf@kernel.org \
--to=balbi@kernel.org \
--cc=andrzej.p@collabora.com \
--cc=anurag.kumar.vulisha@xilinx.com \
--cc=fei.yang@intel.com \
--cc=gregkh@linuxfoundation.org \
--cc=jackp@codeaurora.org \
--cc=john.stultz@linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=stable@vger.kernel.org \
--cc=tejas.joglekar@synopsys.com \
--cc=thinhn@synopsys.com \
--cc=tkjos@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).