path: root/drivers/usb/core/hub.c
diff options
authorAlan Stern <stern@rowland.harvard.edu>2012-10-19 11:03:39 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-10-24 14:51:22 -0700
commitbfd1e910139be73fb0783a0b3171fc79e6afa031 (patch)
treed44b5d70c611c128ad5a511560905b9a834c2c1d /drivers/usb/core/hub.c
parent969ddcfc95c9a1849114fb72466d2fdea70f1d48 (diff)
USB: speed up usb_bus_resume()
This patch (as1620) speeds up USB root-hub resumes in the common case where every enabled port has its suspend feature set (which currently will be true for every runtime resume of the root hub). If all the enabled ports are suspended then resuming the root hub won't resume any of the downstream devices. In this case there's no need for a Resume Recovery delay, because that delay is meant to give devices a chance to get ready for active use. To keep track of the port suspend features, the patch adds a "port_is_suspended" flag to struct usb_device. This has to be tracked separately from the device's state; it's entirely possible for a USB-2 device to be suspended while the suspend feature on its parent port is clear. The reason is that devices will go into suspend whenever their parent hub does. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reviewed-by: Peter Chen <peter.chen@freescale.com> Tested-by: Peter Chen <peter.chen@freescale.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/core/hub.c')
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 64854d76f52..e729e94cb75 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2876,6 +2876,7 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
(PMSG_IS_AUTO(msg) ? "auto-" : ""),
usb_set_device_state(udev, USB_STATE_SUSPENDED);
+ udev->port_is_suspended = 1;
@@ -3040,6 +3041,7 @@ int usb_port_resume(struct usb_device *udev, pm_message_t msg)
if (status == 0) {
+ udev->port_is_suspended = 0;
if (hub_is_superspeed(hub->hdev)) {
if (portchange & USB_PORT_STAT_C_LINK_STATE)
clear_port_feature(hub->hdev, port1,