When there's an xHCI host power loss after a suspend from memory, the USB
core attempts to reset and verify the USB devices that are attached to the
system. The xHCI driver has to reallocate those devices, since the
hardware lost all knowledge of them during the power loss.
When a hub is plugged in, and the host loses power, the xHCI hardware
structures are not updated to say the device is a hub. This is usually
done in hub_configure() when the USB hub is detected. That function is
skipped during a reset and verify by the USB core, since the core restores
the old configuration and alternate settings, and the hub driver has no
idea this happened. This bug makes the xHCI host controller reject the
enumeration of low speed devices under the resumed hub.
Therefore, make the USB core re-setup the internal xHCI hub device
information by calling update_hub_device() when hub_activate() is called
for a hub reset resume. After a host power loss, all devices under the
roothub get a reset-resume or a disconnect.
Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
---
Alan,
Is calling hub_port_logical_disconnect() if the xHCI driver can't
configure the hub structures correctly the right thing to do? At that
point, any low speed device plugged into the hub probably isn't going to
work, and I suspect any new children hubs won't work either.
Sarah Sharp
drivers/usb/core/hub.c | 19 +++++++++++++++++++
1 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 27115b4..03dcb6a 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -677,6 +677,8 @@ static void hub_init_func3(struct work_struct *ws);
static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
{
struct usb_device *hdev = hub->hdev;
+ struct usb_hcd *hcd;
+ int ret;
int port1;
int status;
bool need_debounce_delay = false;
@@ -715,6 +717,23 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
usb_autopm_get_interface_no_resume(
to_usb_interface(hub->intfdev));
return; /* Continues at init2: below */
+ } else if (type == HUB_RESET_RESUME) {
+ /* The internal host controller state for the hub device
+ * may be gone after a host power loss on system resume.
+ * Update the device's info so the HW knows it's a hub.
+ */
+ hcd = bus_to_hcd(hdev->bus);
+ if (hcd->driver->update_hub_device) {
+ ret = hcd->driver->update_hub_device(hcd, hdev,
+ &hub->tt, GFP_KERNEL);
+ if (ret < 0) {
+ hub_port_logical_disconnect(
+ hdev->parent,
+ hdev->portnum);
+ return;
+ }
+ }
+ hub_power_on(hub, true);
} else {
hub_power_on(hub, true);
}
--
1.6.3.3
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