[PATCH 4.9 10/62] usb: handle warm-reset port requests on hub resume

Greg Kroah-Hartman
2019-11-04T22:27:55Z

From: Jan-Marek Glogowski <glogow@fbihome.de>

[ Upstream commit 4fdc1790e6a9ef22399c6bc6e63b80f4609f3b7e ]

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 the root hub, the hub
therefore resumes and the HCDs status_urb isn't yet available.
If a warm-reset request is detected, this sets the hubs event_bits,
which will prevent any auto-suspend and allows the hubs workqueue
to warm-reset the port later in port_event.

Signed-off-by: Jan-Marek Glogowski <glogow@fbihome.de>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/core/hub.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 63646dc3ca27d..4a87cc4783404 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -102,6 +102,8 @@ 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 inline char *portspeed(struct usb_hub *hub, int portstatus)
{
@@ -1108,6 +1110,11 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
USB_PORT_FEAT_ENABLE);
}

+ /* Make sure a warm-reset request is handled by port_event */
+ if (type == HUB_RESUME &&
+ hub_port_warm_reset_required(hub, port1, portstatus))
+ set_bit(port1, hub->event_bits);
+
/*
* Add debounce if USB3 link is in polling/link training state.
* Link will automatically transition to Enabled state after
--
2.20.1