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From: Jun Li <jun.li@nxp.com>
To: Jack Pham <jackp@codeaurora.org>,
	Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
	John Stultz <john.stultz@linaro.org>,
	Amit Pundir <amit.pundir@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>
Cc: Felipe Balbi <balbi@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"linux-usb@vger.kernel.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 07:52:32 +0000	[thread overview]
Message-ID: <VI1PR04MB5935CF921A06041BA8C16A2C89FF9@VI1PR04MB5935.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20210818012859.GB30805@jackp-linux.qualcomm.com>



> -----Original Message-----
> From: jackp=codeaurora.org@mg.codeaurora.org
> <jackp=codeaurora.org@mg.codeaurora.org> On Behalf Of Jack Pham
> Sent: Wednesday, August 18, 2021 9:29 AM
> To: Thinh Nguyen <Thinh.Nguyen@synopsys.com>; John Stultz
> <john.stultz@linaro.org>; Amit Pundir <amit.pundir@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>; Jun Li <jun.li@nxp.com>
> Cc: 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
> 
> 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!

Applied the patch and tested on iMX8MP, can't see L1 sleep event of below in ftrace:
"irq/48-dwc3-557     [000] d..1   264.478691: dwc3_event: event (00020601): Suspend [U2]"
by connecting to USB2 port of my Dell host, so

Tested-by: Jun Li <jun.li@nxp.com>
Reviewed-by: Jun Li <jun.li@nxp.com>

> 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  7:52 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-12  8:26 [PATCH] usb: dwc3: Decouple USB 2.0 L1 & L2 events 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 [this message]
2021-08-18  9:09   ` Amit Pundir
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

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