linux/drivers/usb/core
Alan Stern 05768918b9 USB: improve port transitions when EHCI starts up
It seems to be getting more common recently for EHCI host controllers
to be probed after their companion UHCI or OHCI controllers.  This may
be caused partly by splitting the ehci-pci driver out from ehci-hcd,
or it may be caused by changes in the way the kernel does driver
probing.

Regardless, it has a tendency to cause problems.  When an EHCI
controller is initialized, it takes ownership of all the ports away
from the companions.  In effect, it forcefully disconnects all the USB
devices that may already be using a companion controller.

This patch (as1672b) tries to make the transition more orderly by
deconfiguring the root hubs for all the companion controllers before
initializing the EHCI controller, and reconfiguring them afterward.
The result is a soft disconnect rather than a hard one.

Internally, the patch refactors the code involved in associating EHCI
controllers with their companions.  The old approach, in which a
single function is called with an argument telling it what to do (the
companion_action enum), has been replaced with a scheme using multiple
callback functions, each performing a single task.

This patch won't solve all the problems people encounter when their
EHCI controllers start up, but it will at least reduce the number of
error messages generated by the unexpected disconnections.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Jenya Y <jy.gerstmaier@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-28 14:45:57 -07:00
..
buffer.c USB: Core: Fix minor coding style issues 2011-01-22 19:35:39 -08:00
config.c usb: Fail a get config when the port is powered off. 2012-09-10 13:04:01 -07:00
devices.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
devio.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
driver.c USB: remove CONFIG_USB_SUSPEND option 2013-03-28 11:10:22 -07:00
endpoint.c usb/endpoint: Set release callback in the struct device_type instead of in the device itself directly 2012-08-20 14:38:08 -07:00
file.c USB: rename the usb misc class from "usb" to "usbmisc" 2012-06-13 15:37:13 -07:00
generic.c USB: avoid error messages when a device is disconnected 2013-03-28 11:05:52 -07:00
hcd-pci.c USB: improve port transitions when EHCI starts up 2013-03-28 14:45:57 -07:00
hcd.c USB: remove CONFIG_USB_SUSPEND option 2013-03-28 11:10:22 -07:00
hub.c USB: remove CONFIG_USB_SUSPEND option 2013-03-28 11:10:22 -07:00
hub.h usb: add usb port auto power off mechanism 2013-01-25 10:14:20 -08:00
Kconfig USB: remove CONFIG_USB_SUSPEND option 2013-03-28 11:10:22 -07:00
Makefile usb: Add driver/usb/core/(port.c,hub.h) files 2013-01-18 15:49:00 -08:00
message.c usb/core: consider link speed while looking at bMaxPower 2013-01-11 16:16:01 -08:00
notify.c usb: Add export.h for EXPORT_SYMBOL/THIS_MODULE where needed 2011-10-31 19:31:25 -04:00
otg_whitelist.h USB: fix codingstyle issues in drivers/usb/core/*.h 2008-02-01 14:35:07 -08:00
port.c USB: remove CONFIG_USB_SUSPEND option 2013-03-28 11:10:22 -07:00
quirks.c USB: Add device quirk for Microsoft VX700 webcam 2013-01-11 16:01:07 -08:00
sysfs.c USB: remove CONFIG_USB_SUSPEND option 2013-03-28 11:10:22 -07:00
urb.c USB: fix urb-poison imbalance 2013-03-25 13:48:27 -07:00
usb-acpi.c usb/acpi: binding xhci root hub usb port with ACPI 2013-03-25 10:39:17 -07:00
usb.c USB: remove CONFIG_USB_SUSPEND option 2013-03-28 11:10:22 -07:00
usb.h USB: remove CONFIG_USB_SUSPEND option 2013-03-28 11:10:22 -07:00