[PATCH v3] common: usb-hub: Reset hub port before scanning

[Shantur Rathore]

Hi Marex,

On Sat, Dec 9, 2023 at 6:12 PM Shantur Rathore <i at shantur.com> 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.
> Mostly in these scenarios the hub port is powered before the USB
> controller is enabled, this can lead to some devices in unexpected
> state.
>
> 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.
>
> 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.
>
> Tested working after this patch:
> 1. AMicro AM8180 based NVME to USB Adapter
> 2. Kingston DataTraveler 3.0
> 3. GenesysLogic USB3.0 Hub
>
> The drives were tested while connected directly and via the hub.
>
> Signed-off-by: Shantur Rathore <i at shantur.com>
>
> ---
>
> Changes in v3:
> - Split up patches as seperate series
>
> Changes in v2:
> - As requested, added fix for regulator-always-on in RockPro64
>
>  common/usb_hub.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/common/usb_hub.c b/common/usb_hub.c
> index 70279f301d..3fb7e14d10 100644
> --- a/common/usb_hub.c
> +++ b/common/usb_hub.c
> @@ -174,8 +174,10 @@ static void usb_hub_power_on(struct usb_hub_device *hub)
>
>         debug("enabling power on all ports\n");
>         for (i = 0; i < dev->maxchild; i++) {
> +               usb_set_port_feature(dev, i + 1, USB_PORT_FEAT_RESET);
> +               debug("Reset : port %d returns %lX\n", i + 1, dev->status);
>                 usb_set_port_feature(dev, i + 1, USB_PORT_FEAT_POWER);
> -               debug("port %d returns %lX\n", i + 1, dev->status);
> +               debug("PowerOn : port %d returns %lX\n", i + 1, dev->status);
>         }
>
>  #ifdef CONFIG_SANDBOX
> --
> 2.40.1
>

Do you think it is the right time to get this in early so it can be
tested for a longer time before the next release ?

Kind regards,
Shantur