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| author | Todd E Brandt <todd.e.brandt@linux.intel.com> | 2014-05-19 10:55:32 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-05-27 16:11:49 -0700 |
| commit | 6fecd4f2a58c60028b1a75deefcf111516d3f836 (patch) | |
| tree | 2bb7aded8a2e19b7f54330d6b8a28d910436ecd1 /drivers/usb/core/hub.c | |
| parent | 0a939993bff117d3657108ca13b011fc0378aedb (diff) | |
| download | blackbird-op-linux-6fecd4f2a58c60028b1a75deefcf111516d3f836.tar.gz blackbird-op-linux-6fecd4f2a58c60028b1a75deefcf111516d3f836.zip | |
USB: separate usb_address0 mutexes for each bus
This patch creates a separate instance of the usb_address0 mutex for each USB
bus, and attaches it to the usb_bus device struct. This allows devices on
separate buses to be enumerated in parallel; saving time.
In the current code, there is a single, global instance of the usb_address0
mutex which is used for all devices on all buses. This isn't completely
necessary, as this mutex is only needed to prevent address0 collisions for
devices on the *same* bus (usb 2.0 spec, sec 4.6.1). This superfluous coverage
can cause additional delay in system resume on systems with multiple hosts
(up to several seconds depending on what devices are attached).
Signed-off-by: Todd Brandt <todd.e.brandt@linux.intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
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 | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 090469ebfcff..726fa072c3fe 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -4016,8 +4016,6 @@ static int hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1, int retry_counter) { - static DEFINE_MUTEX(usb_address0_mutex); - struct usb_device *hdev = hub->hdev; struct usb_hcd *hcd = bus_to_hcd(hdev->bus); int i, j, retval; @@ -4040,7 +4038,7 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1, if (oldspeed == USB_SPEED_LOW) delay = HUB_LONG_RESET_TIME; - mutex_lock(&usb_address0_mutex); + mutex_lock(&hdev->bus->usb_address0_mutex); /* Reset the device; full speed may morph to high speed */ /* FIXME a USB 2.0 device may morph into SuperSpeed on reset. */ @@ -4317,7 +4315,7 @@ fail: hub_port_disable(hub, port1, 0); update_devnum(udev, devnum); /* for disconnect processing */ } - mutex_unlock(&usb_address0_mutex); + mutex_unlock(&hdev->bus->usb_address0_mutex); return retval; } |
