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From:   Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
To:     Stefan Wahren <stefan.wahren@i2se.com>,
        Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
CC:     Grigor Tovmasyan <Grigor.Tovmasyan@synopsys.com>,
        Doug Anderson <dianders@chromium.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC] usb: dwc2: power off during shutdown
Thread-Topic: [PATCH RFC] usb: dwc2: power off during shutdown
Thread-Index: AQHUQdnrerw4ENQnyUeZCj/DHLE7ag==
Date:   Wed, 5 Sep 2018 08:37:03 +0000
Message-ID: <410670D7E743164D87FA6160E7907A56013A761B2B@am04wembxa.internal.synopsys.com>
References: <1535795683-3788-1-git-send-email-stefan.wahren@i2se.com>
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Hi Stefan,=0A=
=0A=
On 9/1/2018 1:55 PM, Stefan Wahren wrote:=0A=
> Currently USB consumes a lot of power after shutting down a Raspberry Pi =
3=0A=
> (example setup with Ethernet and a keyboard connected). So power off=0A=
> USB on shutdown.=0A=
> =0A=
> Measured on Raspberry Pi 3B with 4.19rc1/multi_v7_defconfig (HDMI, Ethern=
et=0A=
> and a keyboard connected)=0A=
> =0A=
> Before patch: 2.450 W=0A=
> After patch:  2.090 W=0A=
> =0A=
=0A=
Could you please elaborate. Power measurements done after shutdown? Why =0A=
your setup continue consume power after shutdown? Maybe its =0A=
sleep/hibernation mode?=0A=
=0A=
dwc2 core in your platform which type of power optimization supports: =0A=
partial power down, hibernation or extended hibernation? Please provide =0A=
me GHWCFG4 register value of your core.=0A=
=0A=
Thanks,=0A=
Minas=0A=
=0A=
> Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>=0A=
> ---=0A=
>   drivers/usb/dwc2/platform.c | 31 +++++++++++--------------------=0A=
>   1 file changed, 11 insertions(+), 20 deletions(-)=0A=
> =0A=
> diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c=0A=
> index 9a53a58..eeba40a 100644=0A=
> --- a/drivers/usb/dwc2/platform.c=0A=
> +++ b/drivers/usb/dwc2/platform.c=0A=
> @@ -304,17 +304,11 @@ static int dwc2_lowlevel_hw_init(struct dwc2_hsotg =
*hsotg)=0A=
>   }=0A=
>   =0A=
>   /**=0A=
> - * dwc2_driver_remove() - Called when the DWC_otg core is unregistered w=
ith the=0A=
> - * DWC_otg driver=0A=
> + * dwc2_driver_shutdown() - Called on device shutdown=0A=
>    *=0A=
>    * @dev: Platform device=0A=
> - *=0A=
> - * This routine is called, for example, when the rmmod command is execut=
ed. The=0A=
> - * device may or may not be electrically present. If it is present, the =
driver=0A=
> - * stops device processing. Any resources used on behalf of this device =
are=0A=
> - * freed.=0A=
>    */=0A=
> -static int dwc2_driver_remove(struct platform_device *dev)=0A=
> +static void dwc2_driver_shutdown(struct platform_device *dev)=0A=
>   {=0A=
>   	struct dwc2_hsotg *hsotg =3D platform_get_drvdata(dev);=0A=
>   =0A=
> @@ -329,27 +323,24 @@ static int dwc2_driver_remove(struct platform_devic=
e *dev)=0A=
>   =0A=
>   	reset_control_assert(hsotg->reset);=0A=
>   	reset_control_assert(hsotg->reset_ecc);=0A=
> -=0A=
> -	return 0;=0A=
>   }=0A=
>   =0A=
>   /**=0A=
> - * dwc2_driver_shutdown() - Called on device shutdown=0A=
> + * dwc2_driver_remove() - Called when the DWC_otg core is unregistered w=
ith the=0A=
> + * DWC_otg driver=0A=
>    *=0A=
>    * @dev: Platform device=0A=
>    *=0A=
> - * In specific conditions (involving usb hubs) dwc2 devices can create a=
=0A=
> - * lot of interrupts, even to the point of overwhelming devices running=
=0A=
> - * at low frequencies. Some devices need to do special clock handling=0A=
> - * at shutdown-time which may bring the system clock below the threshold=
=0A=
> - * of being able to handle the dwc2 interrupts. Disabling dwc2-irqs=0A=
> - * prevents reboots/poweroffs from getting stuck in such cases.=0A=
> + * This routine is called, for example, when the rmmod command is execut=
ed. The=0A=
> + * device may or may not be electrically present. If it is present, the =
driver=0A=
> + * stops device processing. Any resources used on behalf of this device =
are=0A=
> + * freed.=0A=
>    */=0A=
> -static void dwc2_driver_shutdown(struct platform_device *dev)=0A=
> +static int dwc2_driver_remove(struct platform_device *dev)=0A=
>   {=0A=
> -	struct dwc2_hsotg *hsotg =3D platform_get_drvdata(dev);=0A=
> +	dwc2_driver_shutdown(dev);=0A=
>   =0A=
> -	disable_irq(hsotg->irq);=0A=
> +	return 0;=0A=
>   }=0A=
>   =0A=
>   /**=0A=
> =0A=
=0A=