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| 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 /lib/percpu_ida.c | |
| parent | 342a74934197386e065e8ef00014e6f0cb5effe6 (diff) | |
| download | op-kernel-dev-600856c231ccb0cbf8afcf09066a8ab2a93ab03d.zip op-kernel-dev-600856c231ccb0cbf8afcf09066a8ab2a93ab03d.tar.gz | |
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 'lib/percpu_ida.c')
0 files changed, 0 insertions, 0 deletions
