[PATCH] common: usb-hub: Reset hub port before scanning

[Shantur Rathore]

On Sun, Nov 19, 2023 at 11:03 PM Shantur Rathore <i at shantur.com> wrote:
>
> Hi Marek,
>
> On Sun, Nov 19, 2023 at 8:53 PM Marek Vasut <marex at denx.de> wrote:
> >
> > On 11/10/23 15:13, Shantur Rathore wrote:
> > > Currently when a hub is turned on, all the ports are powered on.
> > > This works well for hubs which have individual power control.
> > >
> > > For the hubs without individual power control this has no effect.
> >
> > OK
> >
> > > Mostly in these scenarios the hub port is powered before the USB
> > > controller is enabled, this can lead to some devices in unexpected
> > > state.
> >
> > This ^ part needs clarification.
> >
> > Which devices are in incorrect state, the ones connected to the hub
> > downstream facing ports ?
> >
>
> In my case RockPro64, the power to usb ports onboard is controlled by
> a regulator.
> This regulator is enabled as part of init  as here
> https://github.com/u-boot/u-boot/blob/master/arch/arm/dts/rk3399-rockpro64.dtsi#L177
>
> On init, the usb devices connected to the port are powered up, in my
> case AM8180 (a RTL9210 based ) NVMe to USB enclosure with UAS.
> But the usb controller is only enabled at 'usb start' and by this time
> the device is in some state that it doesn't get detected.
>
> One way to make sure the devices connected to the ports are in an
> initialising state is by issuing a port reset before scanning the
> port.
>
> > > With this patch, we explicitly reset the port while powering up hub
> > > This resets the port for hubs without port power control and has
> > > no effect on hubs with port power control as the port is still off.
> >
> > Should common/usb_hub.c usb_hub_port_connect_change() trigger the reset?
> >
> > Could it be you do not get a connect change event ?
>
> Yes, that's correct there is no connect change event while scanning the port.
>
> >
> > > Before this patch AMicro AM8180 based NVME to USB adapter won't be
> > > detected as a USB3.0 Mass Storage device but with this it works as
> > > expected.
> >
> > Do you have HUB power control ?
> >
> > I recall there was some companion hub discussion recently.
>
> The onboard ports don't have separate power control, only the
> regulator as explained above.
>
> Kind regards,
> Shantur

PS:

If the usb device is kept disconnected on init but connected after 'usb start'
while U-boot is scanning usb buses but hasn't scanned the bus the
device is connected to, the usb storage device is detected.

Also, I just tried -
https://patchwork.ozlabs.org/project/uboot/list/?series=379807
and it doesn't fix the issue.