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

Shantur Rathore i at shantur.com
Fri Nov 10 15:09:32 CET 2023


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.
---
 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 85c0822d8b..06fe436add 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



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