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

Peter Chen
2020-06-29T07:38:23Z

On Mon, Jun 29, 2020 at 2:04 PM Chunfeng Yun <chunfeng.yun@mediatek.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?

Peter

>
> Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.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
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