If a port is powered-off, or in the process of being powered-off, prevent
khubd from operating on it. Otherwise, the following sequence of events
leading to an unintended disconnect may occur:
Events:
(0) <set pm_qos_no_poweroff to '0' for port1>
(1) hub 2-2:1.0: hub_resume
(2) hub 2-2:1.0: port 1: status 0301 change 0000
(3) hub 2-2:1.0: state 7 ports 4 chg 0002 evt 0000
(4) hub 2-2:1.0: port 1, power off status 0000, change 0000, 12 Mb/s
(5) usb 2-2.1: USB disconnect, device number 5
Description:
(1) hub is resumed before sending a ClearPortFeature request
(2) hub_activate() notices the port is connected and sets
hub->change_bits for the port
(3) hub_events() starts, but at the same time the port suspends
(4) hub_connect_change() sees the disabled port and triggers disconnect
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/usb/core/hub.c | 38 +++++++++++++++++++++++++++++++++-----
1 files changed, 33 insertions(+), 5 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index d86548edcc36..0fa13a52b52a 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -4654,6 +4654,35 @@ static int hub_handle_remote_wakeup(struct usb_hub *hub, unsigned int port,
return connect_change;
}
+static void put_port(struct usb_port *port_dev, int *port1)
+{
+ if (!port_dev)
+ return;
+
+ pm_runtime_put_sync(&port_dev->dev);
+ (*port1)++;
+}
+
+static struct usb_port *next_active_port(struct usb_hub *hub, int *port1)
+{
+ struct usb_device *hdev = hub->hdev;
+
+ while (*port1 <= hdev->maxchild) {
+ struct usb_port *port_dev = hub->ports[*port1 - 1];
+
+ pm_runtime_get_noresume(&port_dev->dev);
+ pm_runtime_barrier(&port_dev->dev);
+ if (pm_runtime_active(&port_dev->dev))
+ return port_dev;
+ put_port(port_dev, port1);
+ }
+
+ return NULL;
+}
+
+#define for_each_pm_active_port(i, p, h) \
+ for (i = 1; (p = next_active_port(h, &i)); put_port(p, &i))
+
static void hub_events(void)
{
struct list_head *tmp;
@@ -4661,6 +4690,7 @@ static void hub_events(void)
struct usb_interface *intf;
struct usb_hub *hub;
struct device *hub_dev;
+ struct usb_port *port_dev;
u16 hubstatus;
u16 hubchange;
u16 portstatus;
@@ -4739,7 +4769,7 @@ static void hub_events(void)
}
/* deal with port status changes */
- for (i = 1; i <= hdev->maxchild; i++) {
+ for_each_pm_active_port(i, port_dev, hub) {
if (test_bit(i, hub->busy_bits))
continue;
connect_change = test_bit(i, hub->change_bits);
@@ -4775,8 +4805,7 @@ static void hub_events(void)
* Works at least with mouse driver.
*/
if (!(portstatus & USB_PORT_STAT_ENABLE)
- && !connect_change
- && hub->ports[i - 1]->child) {
+ && !connect_change && port_dev->child) {
dev_err (hub_dev,
"port %i "
"disabled by hub (EMI?), "
@@ -4838,8 +4867,7 @@ static void hub_events(void)
*/
if (hub_port_warm_reset_required(hub, portstatus)) {
int status;
- struct usb_device *udev =
- hub->ports[i - 1]->child;
+ struct usb_device *udev = port_dev->child;
dev_dbg(hub_dev, "warm reset port %d\n", i);
if (!udev ||
--
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