linux/drivers/usb/core
Sarah Sharp 4f43447e62 USB: Ignore port state until reset completes.
The port reset code bails out early if the current connect status is
cleared (device disconnected).  If we're issuing a hot reset, it may
also look at the link state before the reset is finished.

Section 10.14.2.6 of the USB 3.0 spec says that when a port enters the
Error state or Resetting state, the port connection bit retains the
value from the previous state.  Therefore we can't trust it until the
reset finishes.  Also, the xHCI spec section 4.19.1.2.5 says software
shall ignore the link state while the port is resetting, as it can be in
an unknown state.

The port state during reset is also unknown for USB 2.0 hubs.  The hub
sends a reset signal by driving the bus into an SE0 state.  This
overwhelms the "connect" signal from the device, so the port can't tell
whether anything is connected or not.

Fix the port reset code to ignore the port link state and current
connect bit until the reset finishes, and USB_PORT_STAT_RESET is
cleared.

Remove the check for USB_PORT_STAT_C_BH_RESET in the warm reset case,
because it's redundant.  When the warm reset finishes, the port reset
bit will be cleared at the same time USB_PORT_STAT_C_BH_RESET is set.
Remove the now-redundant check for a cleared USB_PORT_STAT_RESET bit
in the code to deal with the finished reset.

This patch should be backported to all stable kernels.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable@vger.kernel.org
2013-01-03 14:10:26 -08:00
..
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 USB: hub_for_each_child should skip unconnected ports 2012-10-24 14:51:21 -07:00
devio.c usbdevfs: Fix broken scatter-gather transfer 2012-10-17 13:41:34 -07:00
driver.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-12-13 12:00:02 -08:00
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: fix authorization and claimed port logic 2012-11-15 16:56:22 -08:00
hcd-pci.c USB: add NO_D3_DURING_SLEEP flag and revert 151b612847 2012-06-13 13:11:39 -07:00
hcd.c Merge 3.7-rc6 into usb-next. 2012-11-16 18:46:21 -08:00
hub.c USB: Ignore port state until reset completes. 2013-01-03 14:10:26 -08:00
Kconfig USB: remove CONFIG_EXPERIMENTAL dependancies 2012-09-17 23:00:15 -07:00
Makefile usb: Bind devices to ACPI devices when possible 2012-05-11 17:06:13 -07:00
message.c USB: core: Free the allocated memory before exiting on error 2012-11-21 13:32:26 -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
quirks.c Merge 3.6-rc6 into usb-next 2012-09-16 20:42:46 -07:00
sysfs.c usb: convert USB_QUIRK_RESET_MORPHS to USB_QUIRK_RESET 2012-08-20 14:38:08 -07:00
urb.c USB: report submission of active URBs 2012-11-11 18:10:46 -08:00
usb-acpi.c Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2012-10-08 07:14:06 +09:00
usb.c usb-core: remove CONFIG_HOTPLUG ifdefs 2012-11-21 13:27:16 -08:00
usb.h usb/acpi: Store info on device removability. 2012-09-10 13:04:01 -07:00