On plug-in of my USB-C device, its USB_SS_PORT_LS_SS_INACTIVE link state bit is set. Greping all the kernel for this bit shows that the port status requests a warm-reset this way. This just happens, if its the only device on that hub and the hub resumes, so we don't call port_event, which would otherwise warm-reset ports. The device works ok without this patch, if there is already any other device connected to the hub. Signed-off-by: Jan-Marek Glogowski <glogow@xxxxxxxxxx> --- drivers/usb/core/hub.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 1d1e61e..21a38d3 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -108,6 +108,16 @@ EXPORT_SYMBOL_GPL(ehci_cf_port_reset_rwsem); static void hub_release(struct kref *kref); static int usb_reset_and_verify_device(struct usb_device *udev); static int hub_port_disable(struct usb_hub *hub, int port1, int set_state); +static bool hub_port_warm_reset_required(struct usb_hub *hub, int port1, + u16 portstatus); +static int hub_port_reset(struct usb_hub *hub, int port1, + struct usb_device *udev, unsigned int delay, bool warm); + +#define HUB_ROOT_RESET_TIME 60 /* times are in msec */ +#define HUB_SHORT_RESET_TIME 10 +#define HUB_BH_RESET_TIME 50 +#define HUB_LONG_RESET_TIME 200 +#define HUB_RESET_TIMEOUT 800 static inline char *portspeed(struct usb_hub *hub, int portstatus) { @@ -1122,6 +1132,9 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type) USB_SS_PORT_LS_POLLING)) need_debounce_delay = true; + if (hub_port_warm_reset_required(hub, port1, portstatus)) + hub_port_reset(hub, port1, udev, HUB_BH_RESET_TIME, true); + /* Clear status-change flags; we'll debounce later */ if (portchange & USB_PORT_STAT_C_CONNECTION) { need_debounce_delay = true; @@ -2653,12 +2666,6 @@ static unsigned hub_is_wusb(struct usb_hub *hub) #define SET_CONFIG_TRIES (2 * (use_both_schemes + 1)) #define USE_NEW_SCHEME(i, scheme) ((i) / 2 == (int)scheme) -#define HUB_ROOT_RESET_TIME 60 /* times are in msec */ -#define HUB_SHORT_RESET_TIME 10 -#define HUB_BH_RESET_TIME 50 -#define HUB_LONG_RESET_TIME 200 -#define HUB_RESET_TIMEOUT 800 - /* * "New scheme" enumeration causes an extra state transition to be * exposed to an xhci host and causes USB3 devices to receive control -- 2.1.4