path: root/drivers/usb/core
diff options
authorTodd E Brandt <todd.e.brandt@linux.intel.com>2014-05-19 10:55:32 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-05-27 16:11:49 -0700
commit6fecd4f2a58c60028b1a75deefcf111516d3f836 (patch)
tree2bb7aded8a2e19b7f54330d6b8a28d910436ecd1 /drivers/usb/core
parent0a939993bff117d3657108ca13b011fc0378aedb (diff)
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')
2 files changed, 3 insertions, 4 deletions
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index adddc66c9e8d..174eb857a6b4 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -918,6 +918,7 @@ static void usb_bus_init (struct usb_bus *bus)
bus->bandwidth_allocated = 0;
bus->bandwidth_int_reqs = 0;
bus->bandwidth_isoc_reqs = 0;
+ mutex_init(&bus->usb_address0_mutex);
INIT_LIST_HEAD (&bus->bus_list);
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)
- 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;