mirror of https://gitee.com/openkylin/linux.git
879d38e6bc
This patch (as1533) fixes a race between root-hub suspend and remote wakeup. If a wakeup event occurs while a root hub is suspending, it might not cause the suspend to fail. Although the host controller drivers check for pending wakeup events at the start of their bus_suspend routines, they generally do not check for wakeup events while the routines are running. In addition, if a wakeup event occurs any time after khubd is frozen and before the root hub is fully suspended, it might not cause a system sleep transition to fail. For example, the host controller drivers do not fail root-hub suspends when a connect-change event is pending. To fix both these issues, this patch causes hcd_bus_suspend() to query the controller driver's hub_status_data method after a root hub is suspended, if the root hub is enabled for wakeup. Any pending status changes will count as wakeup events, causing the root hub to be resumed and the overall suspend to fail with -EBUSY. A significant point is that not all events are reflected immediately in the status bits. Both EHCI and UHCI controllers notify the CPU when remote wakeup begins on a port, but the port's suspend-change status bit doesn't get set until after the port has completed the transition out of the suspend state, some 25 milliseconds later. Consequently, the patch will interpret any nonzero return value from hub_status_data as indicating a pending event, even if none of the status bits are set in the data buffer. Follow-up patches make the necessary changes to ehci-hcd and uhci-hcd. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: Sarah Sharp <sarah.a.sharp@linux.intel.com> CC: Chen Peter-B29397 <B29397@freescale.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| .. | ||
| Kconfig | ||
| Makefile | ||
| buffer.c | ||
| config.c | ||
| devices.c | ||
| devio.c | ||
| driver.c | ||
| endpoint.c | ||
| file.c | ||
| generic.c | ||
| hcd-pci.c | ||
| hcd.c | ||
| hub.c | ||
| inode.c | ||
| message.c | ||
| notify.c | ||
| otg_whitelist.h | ||
| quirks.c | ||
| sysfs.c | ||
| urb.c | ||
| usb.c | ||
| usb.h | ||