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From:   Minas Harutyunyan <minas.harutyunyan@synopsys.com>
To:     Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "minas.harutyunyan@synopsys.com" <minas.harutyunyan@synopsys.com>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
CC:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-amlogic@lists.infradead.org" 
        <linux-amlogic@lists.infradead.org>,
        "Arthur.Petrosyan@synopsys.com" <Arthur.Petrosyan@synopsys.com>,
        "christianshewitt@gmail.com" <christianshewitt@gmail.com>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH 1/1] usb: dwc2: disable power_down on Amlogic devices
Thread-Topic: [PATCH 1/1] usb: dwc2: disable power_down on Amlogic devices
Thread-Index: AQHUj/GlZFUzpz34P0WIm4puEQupSw==
Date:   Mon, 10 Dec 2018 06:04:26 +0000
Message-ID: <410670D7E743164D87FA6160E7907A56013A7B631D@am04wembxa.internal.synopsys.com>
References: <20181209190129.11870-1-martin.blumenstingl@googlemail.com>
 <20181209190129.11870-2-martin.blumenstingl@googlemail.com>
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On 12/9/2018 11:01 PM, Martin Blumenstingl wrote:=0A=
> Disable power_down by setting the parameter to=0A=
> DWC2_POWER_DOWN_PARAM_NONE. This fixes a problem on various Amlogic=0A=
> Meson SoCs where USB devices are only recognized when plugged in before=
=0A=
> booting Linux. A hot-plugged USB device was not detected even though the=
=0A=
> device got power (my USB thumb drive for example has an LED which lit=0A=
> up).=0A=
> =0A=
> A similar fix was implemented for Rockchip SoCs in commit c216765d3a1def=
=0A=
> ("usb: dwc2: disable power_down on rockchip devices"). That commit=0A=
> suggests that a change in the dwc2 driver is the cause because the=0A=
> default value for the "hibernate" parameter (which then got renamed to=0A=
> "power_down" to support other modes) was changed in the v4.17 merge=0A=
> window with:=0A=
> commit 6d23ee9caa6790 ("Merge tag 'usb-for-v4.17' of git://git.kernel.org=
/pub/scm/linux/kernel/git/balbi/usb into usb-testing").=0A=
> =0A=
> Cc: <stable@vger.kernel.org> # 4.19=0A=
> Suggested-by: Christian Hewitt <christianshewitt@gmail.com>=0A=
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>=
=0A=
=0A=
Acked-by: Minas Harutyunyan <hminas@synopsys.com>=0A=
> ---=0A=
>   drivers/usb/dwc2/params.c | 1 +=0A=
>   1 file changed, 1 insertion(+)=0A=
> =0A=
> diff --git a/drivers/usb/dwc2/params.c b/drivers/usb/dwc2/params.c=0A=
> index 7c1b6938f212..38c813b1d203 100644=0A=
> --- a/drivers/usb/dwc2/params.c=0A=
> +++ b/drivers/usb/dwc2/params.c=0A=
> @@ -111,6 +111,7 @@ static void dwc2_set_amlogic_params(struct dwc2_hsotg=
 *hsotg)=0A=
>   	p->phy_type =3D DWC2_PHY_TYPE_PARAM_UTMI;=0A=
>   	p->ahbcfg =3D GAHBCFG_HBSTLEN_INCR8 <<=0A=
>   		GAHBCFG_HBSTLEN_SHIFT;=0A=
> +	p->power_down =3D DWC2_POWER_DOWN_PARAM_NONE;=0A=
>   }=0A=
>   =0A=
>   static void dwc2_set_amcc_params(struct dwc2_hsotg *hsotg)=0A=
> =0A=
=0A=