linux-usb.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Amit Pundir <amit.pundir@linaro.org>
To: Jack Pham <jackp@codeaurora.org>
Cc: Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
	John Stultz <john.stultz@linaro.org>, Ray Chi <raychi@google.com>,
	Ferry Toth <ftoth@exalondelft.nl>,
	Chunfeng Yun <chunfeng.yun@mediatek.com>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Li Jun <jun.li@nxp.com>, Felipe Balbi <balbi@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-usb@vger.kernel.org, Wesley Cheng <wcheng@codeaurora.org>
Subject: Re: [RFT][PATCH] usb: dwc3: Decouple USB 2.0 L1 & L2 events
Date: Wed, 18 Aug 2021 14:39:11 +0530	[thread overview]
Message-ID: <CAMi1Hd2PwtLmxXS8_bRjtq1QsEoN_PZzFC8E-R+LRV7=tv2U-w@mail.gmail.com> (raw)
In-Reply-To: <20210818012859.GB30805@jackp-linux.qualcomm.com>

On Wed, 18 Aug 2021 at 06:59, Jack Pham <jackp@codeaurora.org> wrote:
>
> On Thu, Aug 12, 2021 at 01:26:35AM -0700, Jack Pham wrote:
> > On DWC_usb3 revisions 3.00a and newer (including DWC_usb31 and
> > DWC_usb32) the GUCTL1 register gained the DEV_DECOUPLE_L1L2_EVT
> > field (bit 31) which when enabled allows the controller in device
> > mode to treat USB 2.0 L1 LPM & L2 events separately.
> >
> > After commit d1d90dd27254 ("usb: dwc3: gadget: Enable suspend
> > events") the controller will now receive events (and therefore
> > interrupts) for every state change when entering/exiting either
> > L1 or L2 states.  Since L1 is handled entirely by the hardware
> > and requires no software intervention, there is no need to even
> > enable these events and unnecessarily notify the gadget driver.
> > Enable the aforementioned bit to help reduce the overall interrupt
> > count for these L1 events that don't need to be handled while
> > retaining the events for full L2 suspend/wakeup.
>
> Hi folks in To:
>
> I'd like to request if any of you could help test this patch on your
> boards to help make sure it doesn't cause any regressions since I know
> some of the recent dwc3 patches from Qualcomm have been found to break
> other devices :(. So I'm hoping to avoid that even for a patch as
> small as this.
>
> Hoping this could be tried out on boards/SoCs such as db845c, hikey960,
> Exynos, the Intel "lakes", etc.  Ideally this needs validation with a
> high-speed connection to a USB 3.x host, which increases the chances
> that USB 2.0 Link Power Management is supported.
>
> The overall goal of this patch is to eliminate events generated for
> L1 entry/exit, so we should see a slight reduction in interrupt counts
> when checking `grep dwc3 /proc/interrupts` for comparable traffic.
>
> Appreciate any feedback and help in testing!

Smoke tested this patch on RB5, running android-mainline (v5.14-rc6)
kernel, with a USB 3.x host.
Pushed/Pulled couple of large files over ADB, hotplugged the cable a
few times and found no obvious regressions.

Tested-by: Amit Pundir <amit.pundir@linaro.org> # for RB5 (sm8250)

Regards,
Amit Pundir

> Thanks,
> Jack
>
> > Signed-off-by: Jack Pham <jackp@codeaurora.org>
> > ---
> >  drivers/usb/dwc3/core.c | 9 +++++++++
> >  drivers/usb/dwc3/core.h | 5 +++--
> >  2 files changed, 12 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > index ba74ad7f6995..719dac228703 100644
> > --- a/drivers/usb/dwc3/core.c
> > +++ b/drivers/usb/dwc3/core.c
> > @@ -1050,6 +1050,15 @@ static int dwc3_core_init(struct dwc3 *dwc)
> >               if (!DWC3_VER_IS_PRIOR(DWC3, 290A))
> >                       reg |= DWC3_GUCTL1_DEV_L1_EXIT_BY_HW;
> >
> > +             /*
> > +              * Decouple USB 2.0 L1 & L2 events which will allow for
> > +              * gadget driver to only receive U3/L2 suspend & wakeup
> > +              * events and prevent the more frequent L1 LPM transitions
> > +              * from interrupting the driver.
> > +              */
> > +             if (!DWC3_VER_IS_PRIOR(DWC3, 300A))
> > +                     reg |= DWC3_GUCTL1_DEV_DECOUPLE_L1L2_EVT;
> > +
> >               if (dwc->dis_tx_ipgap_linecheck_quirk)
> >                       reg |= DWC3_GUCTL1_TX_IPGAP_LINECHECK_DIS;
> >
> > diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> > index 5991766239ba..356b94a7ec70 100644
> > --- a/drivers/usb/dwc3/core.h
> > +++ b/drivers/usb/dwc3/core.h
> > @@ -256,9 +256,10 @@
> >  #define DWC3_GUCTL_HSTINAUTORETRY    BIT(14)
> >
> >  /* Global User Control 1 Register */
> > -#define DWC3_GUCTL1_PARKMODE_DISABLE_SS      BIT(17)
> > +#define DWC3_GUCTL1_DEV_DECOUPLE_L1L2_EVT    BIT(31)
> >  #define DWC3_GUCTL1_TX_IPGAP_LINECHECK_DIS   BIT(28)
> > -#define DWC3_GUCTL1_DEV_L1_EXIT_BY_HW        BIT(24)
> > +#define DWC3_GUCTL1_DEV_L1_EXIT_BY_HW                BIT(24)
> > +#define DWC3_GUCTL1_PARKMODE_DISABLE_SS              BIT(17)
> >
> >  /* Global Status Register */
> >  #define DWC3_GSTS_OTG_IP     BIT(10)
> > --
> > 2.24.0
> >
>
> --
> The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> a Linux Foundation Collaborative Project

  parent reply	other threads:[~2021-08-18  9:09 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-12  8:26 [PATCH] " Jack Pham
2021-08-18  1:28 ` [RFT][PATCH] " Jack Pham
2021-08-18  2:07   ` John Stultz
2021-08-18  7:52   ` Jun Li
2021-08-18  9:09   ` Amit Pundir [this message]
2021-08-18  9:33   ` Andy Shevchenko
2021-08-18 19:48     ` Ferry Toth
2021-08-19 12:26       ` Andy Shevchenko
2021-08-20 12:17       ` Jack Pham
2021-08-19  2:01   ` Thinh Nguyen
2021-08-18  5:08 ` [PATCH] " Felipe Balbi

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='CAMi1Hd2PwtLmxXS8_bRjtq1QsEoN_PZzFC8E-R+LRV7=tv2U-w@mail.gmail.com' \
    --to=amit.pundir@linaro.org \
    --cc=Thinh.Nguyen@synopsys.com \
    --cc=andriy.shevchenko@linux.intel.com \
    --cc=balbi@kernel.org \
    --cc=chunfeng.yun@mediatek.com \
    --cc=ftoth@exalondelft.nl \
    --cc=gregkh@linuxfoundation.org \
    --cc=jackp@codeaurora.org \
    --cc=john.stultz@linaro.org \
    --cc=jun.li@nxp.com \
    --cc=linux-usb@vger.kernel.org \
    --cc=m.szyprowski@samsung.com \
    --cc=raychi@google.com \
    --cc=wcheng@codeaurora.org \
    --subject='Re: [RFT][PATCH] usb: dwc3: Decouple USB 2.0 L1 & L2 events' \
    /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

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).