diff options
| author | Alan Stern <stern@rowland.harvard.edu> | 2014-05-20 18:08:07 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-05-27 16:28:03 -0700 |
| commit | 600856c231ccb0cbf8afcf09066a8ab2a93ab03d (patch) | |
| tree | aa8e9074adccb30ecbd6ac8aa2dce377e0c5a834 /drivers/usb/core/hub.c | |
| parent | 342a74934197386e065e8ef00014e6f0cb5effe6 (diff) | |
USB: mutual exclusion for resetting a hub and power-managing a port
The USB core doesn't properly handle mutual exclusion between
resetting a hub and changing the power states of the hub's ports. We
need to avoid sending port-power requests to the hub while it is being
reset, because such requests cannot succeed.
This patch fixes the problem by keeping track of when a reset is in
progress. At such times, attempts to suspend (power-off) a port will
fail immediately with -EBUSY, and calls to usb_port_runtime_resume()
will update the power_is_on flag and return immediately. When the
reset is complete, hub_activate() will automatically restore each port
to the proper power state.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/core/hub.c')
| -rw-r--r-- | drivers/usb/core/hub.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 726fa072c3fe..5f43c22ba787 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -1276,12 +1276,22 @@ static void hub_quiesce(struct usb_hub *hub, enum hub_quiescing_type type) flush_work(&hub->tt.clear_work); } +static void hub_pm_barrier_for_all_ports(struct usb_hub *hub) +{ + int i; + + for (i = 0; i < hub->hdev->maxchild; ++i) + pm_runtime_barrier(&hub->ports[i]->dev); +} + /* caller has locked the hub device */ static int hub_pre_reset(struct usb_interface *intf) { struct usb_hub *hub = usb_get_intfdata(intf); hub_quiesce(hub, HUB_PRE_RESET); + hub->in_reset = 1; + hub_pm_barrier_for_all_ports(hub); return 0; } @@ -1290,6 +1300,8 @@ static int hub_post_reset(struct usb_interface *intf) { struct usb_hub *hub = usb_get_intfdata(intf); + hub->in_reset = 0; + hub_pm_barrier_for_all_ports(hub); hub_activate(hub, HUB_POST_RESET); return 0; } |