linux-kernel - Re: [PATCH 1/2] usb: mtu3: disable USB2 LPM

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Message-ID: <1593500631.3798.9.camel@mhfsdcap03>
Date:   Tue, 30 Jun 2020 15:03:51 +0800
From:   Chunfeng Yun <chunfeng.yun@...iatek.com>
To:     Peter Chen <hzpeterchen@...il.com>
CC:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Felipe Balbi <felipe.balbi@...ux.intel.com>,
        USB list <linux-usb@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Markus Elfring <Markus.Elfring@....de>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 1/2] usb: mtu3: disable USB2 LPM

On Mon, 2020-06-29 at 15:37 +0800, Peter Chen wrote:
> On Mon, Jun 29, 2020 at 2:04 PM Chunfeng Yun <chunfeng.yun@...iatek.com> wrote:
> >
> > A SuperSpeed device shall include the USB 2.0 extension descriptor
> > and shall support LPM when operating in USB 2.0 HS mode(see usb3.2
> > spec9.6.2.1). But we always don't support it, so disable it by
> > default, otherwise device will enter LPM suspend mode when
> > connected to Win10 system.
> 
> Linux also supports USB2 LPM. Besides, USB-IF CH9 test will check
> LPM support if the device is USB 2.1, how could you deal with it?
Indeed need support it for SS device, I'll check it again, thanks a lot

> 
> Peter
> 
> >
> > Signed-off-by: Chunfeng Yun <chunfeng.yun@...iatek.com>
> > ---
> >  drivers/usb/mtu3/mtu3_core.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/usb/mtu3/mtu3_core.c b/drivers/usb/mtu3/mtu3_core.c
> > index 9dd0216..50d6a40 100644
> > --- a/drivers/usb/mtu3/mtu3_core.c
> > +++ b/drivers/usb/mtu3/mtu3_core.c
> > @@ -604,6 +604,8 @@ static void mtu3_regs_init(struct mtu3 *mtu)
> >         mtu3_clrbits(mbase, U3D_MISC_CTRL, VBUS_FRC_EN | VBUS_ON);
> >         /* enable automatical HWRW from L1 */
> >         mtu3_setbits(mbase, U3D_POWER_MANAGEMENT, LPM_HRWE);
> > +       /* always reject LPM request */
> > +       mtu3_setbits(mbase, U3D_POWER_MANAGEMENT, LPM_MODE(1));
> >
> >         /* use new QMU format when HW version >= 0x1003 */
> >         if (mtu->gen2cp)
> > --
> > 1.9.1
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@...ts.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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