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>
---
v1: This always warm-resets the ports in hub_activate, independent of the
"enum hub_activation_type". Just had a single device to test.
v2: I had the idea about the working device, if there is already a device
connected to the hub and that a resume only on "type == HUB_RESUME" should
be sufficient. This still works for me, but I didn't follow all the
hub_activate callers everywhere and I'm definitly still missing a lot of
knowledge about USB stuff. There is also HUB_RESET_RESUME with a slightly
different code path. I don't know how to trigger this.
v3: code unchanged to v2, so I could abandon my explanation mail, which I
was typing when Gregs mail arrived.
---
drivers/usb/core/hub.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 1d1e61e..e0cc740 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 +1132,11 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
USB_SS_PORT_LS_POLLING))
need_debounce_delay = true;
+ if (type == HUB_RESUME &&
+ 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 +2668,6 @@ 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
