In general we do not want khubd to act on port status changes that are
the result of in progress resets or USB runtime PM operations.
Specifically port power control testing has been able to trigger an
unintended disconnect in hub_port_connect_change(), paraphrasing:

	if ((portstatus & USB_PORT_STAT_CONNECTION) && udev &&
	    udev->state != USB_STATE_NOTATTACHED) {
		if (portstatus & USB_PORT_STAT_ENABLE) {
			/* Nothing to do */
		} else if (udev->state == USB_STATE_SUSPENDED &&
				udev->persist_enabled) {
			...
		} else {
			/* Don't resuscitate */;
		}
	}

...by falling to the "Don't resuscitate" path or missing
USB_PORT_STAT_CONNECTION because usb_port_resume() was in the middle of
modifying the port status.

So, we want a new lock to hold off khubd for a given port while the
child device is being suspended, resumed, or reset.  The lock ordering
rules are now usb_lock_device() => usb_lock_port().  This is mandated by
the device core which may hold the device_lock on the usb_device before
invoking usb_port_{suspend|resume} which in turn take the status_lock on
the usb_port.  We attempt to hold the status_lock for the duration of a
port_event() run, and drop/re-acquire it when needing to take the
device_lock.  The lock is also dropped/re-acquired during
hub_port_reconnect().

This patch also deletes hub->busy_bits as all use cases are now covered
by port PM runtime synchronization or the port->status_lock and it
pushes down usb_device_lock() into usb_remote_wakeup().
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If a port is powered-off, or in the process of being powered-off, prevent
khubd from operating on it.  Otherwise, the following sequence of events
leading to an unintended disconnect may occur:

Events:
(0) <set pm_qos_no_poweroff to '0' for port1>
(1) hub 2-2:1.0: hub_resume
(2) hub 2-2:1.0: port 1: status 0301 change 0000
(3) hub 2-2:1.0: state 7 ports 4 chg 0002 evt 0000
(4) hub 2-2:1.0: port 1, power off status 0000, change 0000, 12 Mb/s
(5) usb 2-2.1: USB disconnect, device number 5

Description:
(1) hub is resumed before sending a ClearPortFeature request
(2) hub_activate() notices the port is connected and sets
    hub->change_bits for the port
(3) hub_events() starts, but at the same time the port suspends
(4) hub_connect_change() sees the disabled port and triggers disconnect
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In preparation for synchronizing port handling with pm_runtime
transitions refactor port handling into its own subroutine.

We expect that clearing some status flags will be required regardless of
the port state, so handle those first and group all non-trivial actions
at the bottom of the routine.

This also splits off the bottom half of hub_port_connect_change() into
hub_port_reconnect() in prepartion for introducing a port->status_lock.
hub_port_reconnect() will expect the port lock to not be held while
hub_port_connect_change() expects to enter with it held.

Other cleanups include:
1/ reflowing to 80 columns
2/ replacing redundant usages of 'hub->hdev' with 'hdev'
3/ consolidate clearing of ->change_bits() in hub_port_connect_change
4/ consolidate calls to usb_reset_device
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

ClearPortFeature(PORT_POWER) on a usb3 port places the port in either a
DSPORT.Powered-off-detect / DSPORT.Powered-off-reset loop, or the
DSPORT.Powered-off state.  There is no way to ensure that RX
terminations will persist in this state, so it is possible a device will
degrade to its usb2 connection.  Prevent this by blocking power-off of a
usb3 port while its usb2 peer is active, and powering on a usb3 port
before its usb2 peer.

By default the latency between peer power-on events is 0.  In order for
the device to not see usb2 active while usb3 is still powering up inject
the hub recommended power_on_good delay.  In support of satisfying the
power_on_good delay outside of hub_power_on() refactor the places where
the delay is consumed to call a new hub_power_on_good_delay() helper.

Finally, because this introduces several new checks for whether a port
is_superspeed, cache that disctinction at port creation so that we don't
need to keep looking up the parent hub device.
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
[alan]: add a 'superspeed' flag to the port
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We want to manipulate ->did_runtime_put in usb_port_runtime_resume(),
but we don't want that to collide with other updates.  Move usb_port
flags to new port-bitmap fields in usb_hub. "did_runtime_put" is renamed
"child_usage_bits" to reflect that it is strictly standing in for the
fact that usb_devices are not the device_model children of their parent
port.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Assume that the peer of a superspeed port is the port with the same id
on the shared_hcd root hub.  This identification scheme is required of
external hubs by the USB3 spec [1].  However, for root hubs, tier mismatch
may be in effect [2].  Tier mismatch can only be enumerated via platform
firmware.  For now, simply perform the nominal association.

A new lock 'usb_port_peer_mutex' is introduced to synchronize port
device add/remove with peer lookups.  It protects peering against
changes to hcd->shared_hcd, hcd->self.root_hub, hdev->maxchild, and
port_dev->child pointers.

[1]: usb 3.1 section 10.3.3
[2]: xhci 1.1 appendix D

Cc: Alan Stern <stern@rowland.harvard.edu>
[alan: usb_port_peer_mutex locking scheme]
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Once usb-acpi has set the port's connect type the usb_device's
->removable attribute can be set in the standard location
set_usb_port_removable().

This also changes behavior in the case where the firmware says that the
port connect type is unknown.  In that case just use the default setting
determined from the hub descriptor.

Note, we no longer pass udev->portnum to acpi_find_child_device() in the
root hub case since:
1/ the usb-core sets this to zero
2/ acpi always expects zero
...just pass zero.
Suggested-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The current port name "portX" is ambiguous.  Before adding more port
messages rename ports to "<hub-device-name>-portX"

This is an ABI change, but the suspicion is that it will go unnoticed as
the port power control implementation has been broken since its
introduction.  If however, someone was relying on the old name we can
add sysfs links from the old name to the new name.

Additionally, it unifies/simplifies port dev_printk messages and modifies
instances of:
	dev_XXX(hub->intfdev, ..."port %d"...
	dev_XXX(&hdev->dev, ..."port%d"...
into:
	dev_XXX(&port_dev->dev, ...

Now that the names are unique usb_port devices it would be nice if they
could be included in /sys/bus/usb.  However, it turns out that this
breaks 'lsusb -t'.  For now, create a dummy port driver so that print
messages are prefixed "usb 1-1-port3" rather than the
subsystem-ambiguous " 1-1-port3".

Finally, it corrects an odd usage of sscanf("port%d") in usb-acpi.c.
Suggested-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

A hub indicates whether it supports per-port power control via the
wHubCharacteristics field in its descriptor.  If it is not supported
a hub will still emulate ClearPortPower(PORT_POWER) requests by
stopping the link state machine.  However, since this does not save
power do not bother suspending.

This also consolidates support checks into a
hub_is_port_power_switchable() helper.
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The USB core doesn't properly handle mutual exclusion between
resetting a hub and changing the power states of the hub's ports.  We
need to avoid sending port-power requests to the hub while it is being
reset, because such requests cannot succeed.

This patch fixes the problem by keeping track of when a reset is in
progress.  At such times, attempts to suspend (power-off) a port will
fail immediately with -EBUSY, and calls to usb_port_runtime_resume()
will update the power_is_on flag and return immediately.  When the
reset is complete, hub_activate() will automatically restore each port
to the proper power state.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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: NTodd Brandt <todd.e.brandt@linux.intel.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The USB_QUIRK_RESET flag indicates that a USB device changes its
identity in some way when it is reset.  It may lose its firmware, its
descriptors may change, or it may switch back to a default mode of
operation.

If a device does this, the kernel needs to avoid resetting it.  Resets
are likely to fail, or worse, succeed while changing the device's
state in a way the system can't detect.

This means we should disable the reset-resume mechanism whenever this
quirk flag is present.  An attempted reset-resume will fail, the
device will be logically disconnected, and later on the hub driver
will rediscover and re-enumerate the device.  This will cause the
appropriate udev events to be generated, so that userspace will have a
chance to switch the device into its normal operating mode, if
necessary.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
CC: Oliver Neukum <oliver@neukum.org>
Reviewed-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When a driver doesn't have pre_reset, post_reset, or reset_resume
methods, the USB core unbinds that driver when its device undergoes a
reset or a reset-resume, and then rebinds it afterward.

The existing straightforward implementation can lead to problems,
because each interface gets unbound and rebound before the next
interface is handled.  If a driver claims additional interfaces, the
claim may fail because the old binding instance may still own the
additional interface when the new instance tries to claim it.

This patch fixes the problem by first unbinding all the interfaces
that are marked (i.e., their needs_binding flag is set) and then
rebinding all of them.

The patch also makes the helper functions in driver.c a little more
uniform and adjusts some out-of-date comments.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: N"Poulain, Loic" <loic.poulain@intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since it is needed outside usbcore and exposed in include/linux/usb.h,
it conflicts with enum dev_state in rt2x00 wireless driver.

Mark it as usb specific to avoid conflicts in the future.
Signed-off-by: NValentina Manea <valentina.manea.m@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

A device should not be able to be used concurrently both by
the server and the client. Claiming the port used by the
shared device ensures no interface drivers bind to it and
that it is not usable from the server.
Signed-off-by: NValentina Manea <valentina.manea.m@gmail.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

PREPARE_[DELAYED_]WORK() are being phased out.  They have few users
and a nasty surprise in terms of reentrancy guarantee as workqueue
considers work items to be different if they don't have the same work
function.

usb_hub->init_work is multiplexed with multiple work functions;
however, the work item is never queued while in-flight, so we can
simply use INIT_DELAYED_WORK() before each queueing.

It would probably be best to route this with other related updates
through the workqueue tree.

Lightly tested.

v2: Greg and Alan confirm that the work item is never queued while
    in-flight.  Simply use INIT_DELAYED_WORK().
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: linux-usb@vger.kernel.org

On disconnect USB3 protocol ports transit from U0 to SS.Inactive to Rx.Detect,
on a recoverable error, the port stays in SS.Inactive and we recover from it by
doing a warm-reset (through usb_device_reset if we have a udev for the port).

If this really is a disconnect we may end up trying the warm-reset anyways,
since khubd may run before the SS.Inactive to Rx.Detect transition, or it
may get skipped if the transition to Rx.Detect happens before khubd gets run.

With a loose connector, or in the case which actually led me to debugging this
bad ACPI firmware toggling Vbus off and on in quick succession, the port
may transition from Rx.Detect to U0 again before khubd gets run. In this case
the device state is unknown really, but khubd happily goes into the resuscitate
an existing device path, and the device driver never gets notified about the
device state being messed up.

If the above scenario happens with a streams using device, as soon as an urb
is submitted to an endpoint with streams, the following appears in dmesg:

ERROR Transfer event for disabled endpoint or incorrect stream ring
@0000000036807420 00000000 00000000 04000000 04078000

Notice how the TRB address is all zeros. I've seen this both on Intel
Pantherpoint and Nec xhci hosts.

Luckily we can detect the U0 to SS.Inactive to Rx.Detect to U0 all having
happened before khubd runs case since the C_LINK_STATE bit gets set in the
portchange bits on the U0 -> SS.Inactive change. This bit will also be set on
suspend / resume, but then it gets cleared by port_hub_init before khubd runs.

So if the C_LINK_STATE bit is set and a warm-reset is not needed, iow the port
is not still in SS.Inactive, and the port still has a connection, then the
device needs to be reset to put it back in a known state.

I've verified that doing the device reset also fixes the transfer event with
all zeros address issue.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>

If streams are still allocated on device-reset or set-interface then the hcd
code implictly frees the streams. Clear host_endpoint->streams in this case
so that if a driver later tries to re-allocate them it won't run afoul of the
device already having streams check in usb_alloc_streams().

Note normally streams still being allocated at reset / set-intf  would be a
driver bug, but this can happen without it being a driver bug on reset-resume.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>

The xHCI driver currently uses a USB core internal field,
udev->lpm_capable, to indicate the xHCI driver knows how to calculate
the LPM timeout values.  If this value is set for the host controller
udev, it means Link PM can be enabled for child devices under that host.

Change the code so the xHCI driver isn't mucking with USB core internal
fields.  Instead, indicate the xHCI driver doesn't support Link PM on
this host by clearing the U1 and U2 exit latencies in the roothub
SuperSpeed Extended Capabilities BOS descriptor.

The code to check for the roothub setting U1 and U2 exit latencies to
zero will also disable LPM for external devices that do that same.  This
was already effectively done with commit
ae8963ad "usb: Don't enable LPM if the
exit latency is zero."  Leave that code in place, so that if a device
sets one exit latency value to zero, but the other is set to a valid
value, LPM is only enabled for the U1 or U2 state that had the valid
value.  This is the same behavior the code had before.

Also, change messages about missing Link PM information from warning
level to info level.  Only print a warning about the first device that
doesn't support LPM, to avoid log spam.  Further, cleanup some
unnecessary line breaks to help people to grep for the error messages.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>

Better check the correct bit on big endian systems too. Shuts
up the following sparse __CHECK_ENDIAN__ warning:

  .../hub.c:3965:32: warning: restricted __le32 degrades to integer
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This error case isn't reported during enumeration.
Signed-off-by: NOliver Neukum <oliver@neukum.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Allow the scheduler to select the best CPU to handle hub initalization
and LED blinking work. This extends idle residency times on idle CPUs
and conserves power.

This functionality is enabled when CONFIG_WQ_POWER_EFFICIENT is selected.

[zoran.markovic@linaro.org: Rebased to latest kernel. Added commit message.
Changed reference from system to power efficient workqueue for LEDs in
check_highspeed() and hub_port_connect_change().]
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Xenia Ragiadakou <burzalodowa@gmail.com>
Cc: Julius Werner <jwerner@chromium.org>
Cc: Krzysztof Mazur <krzysiek@podlesie.net>
Cc: Matthias Beyer <mail@beyermatthias.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Mathias Nyman <mathias.nyman@linux.intel.com>
Cc: Thomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: NShaibal Dutta <shaibal.dutta@broadcom.com>
Signed-off-by: NZoran Markovic <zoran.markovic@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 9df89d85 "usbcore: set
lpm_capable field for LPM capable root hubs" was created under the
assumption that all USB host controllers should have USB 3.0 Link PM
enabled for all devices under the hosts.

Unfortunately, that's not the case.  The xHCI driver relies on knowledge
of the host hardware scheduler to calculate the LPM U1/U2 timeout
values, and it only sets lpm_capable to one for Intel host controllers
(that have the XHCI_LPM_SUPPORT quirk set).

When LPM is enabled for some Fresco Logic hosts, it causes failures with
a AgeStar 3UBT USB 3.0 hard drive dock:

Jan 11 13:59:03 sg-laptop kernel: usb 3-1: new SuperSpeed USB device number 2 using xhci_hcd
Jan 11 13:59:03 sg-laptop kernel: usb 3-1: Set SEL for device-initiated U1 failed.
Jan 11 13:59:08 sg-laptop kernel: usb 3-1: Set SEL for device-initiated U2 failed.
Jan 11 13:59:08 sg-laptop kernel: usb-storage 3-1:1.0: USB Mass Storage device detected
Jan 11 13:59:08 sg-laptop mtp-probe[613]: checking bus 3, device 2: "/sys/devices/pci0000:00/0000:00:1c.3/0000:04:00.0/usb3/3-1"
Jan 11 13:59:08 sg-laptop mtp-probe[613]: bus: 3, device: 2 was not an MTP device
Jan 11 13:59:08 sg-laptop kernel: scsi6 : usb-storage 3-1:1.0
Jan 11 13:59:13 sg-laptop kernel: usb 3-1: Set SEL for device-initiated U1 failed.
Jan 11 13:59:18 sg-laptop kernel: usb 3-1: Set SEL for device-initiated U2 failed.
Jan 11 13:59:18 sg-laptop kernel: usbcore: registered new interface driver usb-storage
Jan 11 13:59:40 sg-laptop kernel: usb 3-1: reset SuperSpeed USB device number 2 using xhci_hcd
Jan 11 13:59:41 sg-laptop kernel: usb 3-1: device descriptor read/8, error -71
Jan 11 13:59:41 sg-laptop kernel: usb 3-1: reset SuperSpeed USB device number 2 using xhci_hcd
Jan 11 13:59:46 sg-laptop kernel: usb 3-1: device descriptor read/8, error -110
Jan 11 13:59:46 sg-laptop kernel: scsi 6:0:0:0: Device offlined - not ready after error recovery
Jan 11 13:59:46 sg-laptop kernel: usb 3-1: USB disconnect, device number 2

lspci for the affected host:

04:00.0 0c03: 1b73:1000 (rev 04) (prog-if 30 [XHCI])
        Subsystem: 1043:1039
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 0, Cache Line Size: 64 bytes
        Interrupt: pin A routed to IRQ 19
        Region 0: Memory at dd200000 (32-bit, non-prefetchable) [size=64K]
        Capabilities: [50] Power Management version 3
                Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0+,D1-,D2-,D3hot+,D3cold-)
                Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [68] MSI: Enable- Count=1/1 Maskable- 64bit+
                Address: 0000000000000000  Data: 0000
        Capabilities: [80] Express (v1) Endpoint, MSI 00
                DevCap: MaxPayload 128 bytes, PhantFunc 0, Latency L0s <2us, L1 <32us
                        ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset-
                DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported-
                        RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+
                        MaxPayload 128 bytes, MaxReadReq 512 bytes
                DevSta: CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr- TransPend-
                LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1, Latency L0 unlimited, L1 unlimited
                        ClockPM- Surprise- LLActRep- BwNot-
                LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- Retrain- CommClk+
                        ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
                LnkSta: Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
        Kernel driver in use: xhci_hcd
        Kernel modules: xhci_hcd

The commit was backported to stable kernels, and will need to be
reverted there as well.
Signed-off-by: NSarah Sharp <sarah.a.sharp@intel.com>
Reported-by: NSergey Galanov <sergey.e.galanov@gmail.com>
Cc: stable@vger.kernel.org

When we are doing compliance test with xHCI, we found that if we
enable CONFIG_USB_SUSPEND and plug in a bad device which causes
over-current condition to the root port, software will not be noticed.
The reason is that current code don't set hub->change_bits in
hub_activate() when over-current happens, and then hub_events() will
not check the port status because it thinks nothing changed.
If CONFIG_USB_SUSPEND is disabled, the interrupt pipe of the hub will
report the change and set hub->event_bits, and then hub_events() will
check what events happened.In this case over-current can be detected.
Signed-off-by: NShen Guang <shenguang10@gmail.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NRahul Bedarkar <rahulbedarkar89@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is a race in the hub driver between hub_disconnect() and
recursively_mark_NOTATTACHED().  This race can be triggered if the
driver is unbound from a device at the same time as the bus's root hub
is removed.  When the race occurs, it can cause an oops:

BUG: unable to handle kernel NULL pointer dereference at 0000015c
IP: [<c16d5fb0>] recursively_mark_NOTATTACHED+0x20/0x60
Call Trace:
 [<c16d5fc4>] recursively_mark_NOTATTACHED+0x34/0x60
 [<c16d5fc4>] recursively_mark_NOTATTACHED+0x34/0x60
 [<c16d5fc4>] recursively_mark_NOTATTACHED+0x34/0x60
 [<c16d5fc4>] recursively_mark_NOTATTACHED+0x34/0x60
 [<c16d6082>] usb_set_device_state+0x92/0x120
 [<c16d862b>] usb_disconnect+0x2b/0x1a0
 [<c16dd4c0>] usb_remove_hcd+0xb0/0x160
 [<c19ca846>] ? _raw_spin_unlock_irqrestore+0x26/0x50
 [<c1704efc>] ehci_mid_remove+0x1c/0x30
 [<c1704f26>] ehci_mid_stop_host+0x16/0x30
 [<c16f7698>] penwell_otg_work+0xd28/0x3520
 [<c19c945b>] ? __schedule+0x39b/0x7f0
 [<c19cdb9d>] ? sub_preempt_count+0x3d/0x50
 [<c125e97d>] process_one_work+0x11d/0x3d0
 [<c19c7f4d>] ? mutex_unlock+0xd/0x10
 [<c125e0e5>] ? manage_workers.isra.24+0x1b5/0x270
 [<c125f009>] worker_thread+0xf9/0x320
 [<c19ca846>] ? _raw_spin_unlock_irqrestore+0x26/0x50
 [<c125ef10>] ? rescuer_thread+0x2b0/0x2b0
 [<c1264ac4>] kthread+0x94/0xa0
 [<c19d0f77>] ret_from_kernel_thread+0x1b/0x28
 [<c1264a30>] ? kthread_create_on_node+0xc0/0xc0

One problem is that recursively_mark_NOTATTACHED() uses the intfdata
value and hub->hdev->maxchild while hub_disconnect() is clearing them.
Another problem is that it uses hub->ports[i] while the port device is
being released.

To fix this race, we need to hold the device_state_lock while
hub_disconnect() changes the values.  (Note that usb_disconnect()
and hub_port_connect_change() already acquire this lock at similar
critical times during a USB device's life cycle.)  We also need to
remove the port devices after maxchild has been set to 0, instead of
before.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Reported-by: N"Du, Changbin" <changbinx.du@intel.com>
Tested-by: N"Du, Changbin" <changbinx.du@intel.com>
CC: <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

CONFIG_USB_DEBUG is going away, so remove the few places in the USB core
that relied on them.

This means that we always now do the "debug" checks for every urb
submitted, which is a good idea, as who knows how many driver bugs we
have been ignoring when people forget to enable this option.  Also, with
the overall speed of USB, doing these extra checks should not cause any
additional overhead.

Also, no longer announce all devices being added to the system if
CONFIG_USB_DEBUG is enabled, as it's not going to be around much longer.
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Change the default enumeration scheme for xhci attached non-SuperSpeed
devices from:

   Reset
   SetAddress [xhci address-device BSR = 0]
   GetDescriptor(8)
   GetDescriptor(18)

...to:

   Reset
   [xhci address-device BSR = 1]
   GetDescriptor(64)
   Reset
   SetAddress [xhci address-device BSR = 0]
   GetDescriptor(18)

...as some devices misbehave when encountering a SetAddress command
prior to GetDescriptor.  There are known legacy devices that require
this scheme, but testing has found at least one USB3 device that fails
enumeration when presented with this ordering.  For now, follow the ehci
case and enable 'new scheme' by default for non-SuperSpeed devices.

To support this enumeration scheme on xhci the AddressDevice operation
needs to be performed twice.  The first instance of the command enables
the HC's device and slot context info for the device, but omits sending
the device a SetAddress command (BSR == block set address request).
Then, after GetDescriptor completes, follow up with the full
AddressDevice+SetAddress operation.

As mentioned before, this ordering of events with USB3 devices causes an
extra state transition to be exposed to xhci.  Previously USB3 devices
would transition directly from 'enabled' to 'addressed' and never need
to underrun responses to 'get descriptor'. We do see the 64-byte
descriptor fetch the correct data, but the following 18-byte descriptor
read after the reset gets:

bLength            = 0
bDescriptorType    = 0
bcdUSB             = 0
bDeviceClass       = 0
bDeviceSubClass    = 0
bDeviceProtocol    = 0
bMaxPacketSize0    = 9

instead of:

bLength            = 12
bDescriptorType    = 1
bcdUSB             = 300
bDeviceClass       = 0
bDeviceSubClass    = 0
bDeviceProtocol    = 0
bMaxPacketSize0    = 9

which results in the discovery process looping until falling back to
'old scheme' enumeration.
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Reported-by: NDavid Moore <david.moore@gmail.com>
Suggested-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>

There is no need to skip querying the config and string descriptors for
unauthorized WUSB devices when usb_new_device is called.  It is allowed
by WUSB spec.  The only action that needs to be delayed until
authorization time is the set config.  This change allows user mode
tools to see the config and string descriptors earlier in enumeration
which is needed for some WUSB devices to function properly on Android
systems.  It also reduces the amount of divergent code paths needed
for WUSB devices.
Signed-off-by: NThomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch adds a check for USB_STATE_NOTATTACHED to the
hub_port_warm_reset_required() workaround for ports that end up in
Compliance Mode in hub_events() when trying to decide which reset
function to use. Trying to call usb_reset_device() with a NOTATTACHED
device will just fail and leave the port broken.
Signed-off-by: NJulius Werner <jwerner@chromium.org>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since DEVICE_ACPI_HANDLE() is now literally identical to
ACPI_HANDLE(), replace it with the latter everywhere and drop its
definition from include/acpi.h.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove a few extra lines and make it clear that all implementations
disable the port by sharing the same line of code.
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>

This patch adds the Port Reset Change flag to the set of bits that are
preemptively cleared on init/resume of a hub. In theory this bit should
never be set unexpectedly... in practice it can still happen if BIOS,
SMM or ACPI code plays around with USB devices without cleaning up
correctly. This is especially dangerous for XHCI root hubs, which don't
generate any more Port Status Change Events until all change bits are
cleared, so this is a good precaution to have (similar to how it's
already done for the Warm Port Reset Change flag).
Signed-off-by: NJulius Werner <jwerner@chromium.org>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Some usb3 devices falsely claim they support usb2 hardware Link PM
when connected to a usb2 port. We only trust hardwired devices
or devices with the later BESL LPM support to be LPM enabled as default.

[Note: Sarah re-worked the original patch to move the code into the USB
core, and updated it to check whether the USB device supports BESL,
instead of checking if the xHCI port it's connected to supports BESL
encoding.]

This patch should be backported to kernels as old as 3.11, that
contain the commit a558ccdc "usb: xhci:
add USB2 Link power management BESL support".  Without this fix, some
USB 3.0 devices will not enumerate or work properly under USB 2.0 ports
on Haswell-ULT systems.
Signed-off-by: NMathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org

How it's supposed to work:
--------------------------

USB 2.0 Link PM is a lower power state that some newer USB 2.0 devices
support.  USB 3.0 devices certified by the USB-IF are required to
support it if they are plugged into a USB 2.0 only port, or a USB 2.0
cable is used.  USB 2.0 Link PM requires both a USB device and a host
controller that supports USB 2.0 hardware-enabled LPM.

USB 2.0 Link PM is designed to be enabled once by software, and the host
hardware handles transitions to the L1 state automatically.  The premise
of USB 2.0 Link PM is to be able to put the device into a lower power
link state when the bus is idle or the device NAKs USB IN transfers for
a specified amount of time.

...but hardware is broken:
--------------------------

It turns out many USB 3.0 devices claim to support USB 2.0 Link PM (by
setting the LPM bit in their USB 2.0 BOS descriptor), but they don't
actually implement it correctly.  This manifests as the USB device
refusing to respond to transfers when it is plugged into a USB 2.0 only
port under the Haswell-ULT/Lynx Point LP xHCI host.

These devices pass the xHCI driver's simple test to enable USB 2.0 Link
PM, wait for the port to enter L1, and then bring it back into L0.  They
only start to break when L1 entry is interleaved with transfers.

Some devices then fail to respond to the next control transfer (usually
a Set Configuration).  This results in devices never enumerating.

Other mass storage devices (such as a later model Western Digital My
Passport USB 3.0 hard drive) respond fine to going into L1 between
control transfers.  They ACK the entry, come out of L1 when the host
needs to send a control transfer, and respond properly to those control
transfers.  However, when the first READ10 SCSI command is sent, the
device NAKs the data phase while it's reading from the spinning disk.
Eventually, the host requests to put the link into L1, and the device
ACKs that request.  Then it never responds to the data phase of the
READ10 command.  This results in not being able to read from the drive.

Some mass storage devices (like the Corsair Survivor USB 3.0 flash
drive) are well behaved.  They ACK the entry into L1 during control
transfers, and when SCSI commands start coming in, they NAK the requests
to go into L1, because they need to be at full power.

Not all USB 3.0 devices advertise USB 2.0 link PM support.  My Point
Grey USB 3.0 webcam advertises itself as a USB 2.1 device, but doesn't
have a USB 2.0 BOS descriptor, so we don't enable USB 2.0 Link PM.  I
suspect that means the device isn't certified.

What do we do about it?
-----------------------

There's really no good way for the kernel to test these devices.
Therefore, the kernel needs to disable USB 2.0 Link PM by default, and
distros will have to enable it by writing 1 to the sysfs file
/sys/bus/usb/devices/../power/usb2_hardware_lpm.  Rip out the xHCI Link
PM test, since it's not sufficient to detect these buggy devices, and
don't automatically enable LPM after the device is addressed.

This patch should be backported to kernels as old as 3.11, that
contain the commit a558ccdc "usb: xhci:
add USB2 Link power management BESL support".  Without this fix, some
USB 3.0 devices will not enumerate or work properly under USB 2.0 ports
on Haswell-ULT systems.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org

Before the USB core resets a device, we need to disable the L1 timeout
for the roothub, if USB 2.0 Link PM is enabled.  Otherwise the port may
transition into L1 in between descriptor fetches, before we know if the
USB device descriptors changed.  LPM will be re-enabled after the
full device descriptors are fetched, and we can confirm the device still
supports USB 2.0 LPM after the reset.

We don't need to wait for the USB device to exit L1 before resetting the
device, since the xHCI roothub port diagrams show a transition to the
Reset state from any of the Ux states (see Figure 34 in the 2012-08-14
xHCI specification update).

This patch should be backported to kernels as old as 3.2, that contain
the commit 65580b43 "xHCI: set USB2
hardware LPM".  That was the first commit to enable USB 2.0
hardware-driven Link Power Management.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org

Signed-off-by: NMatthias Beyer <mail@beyermatthias.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

including:

- removing of trailing whitespace
- removing spaces before array indexing (foo [] to foo[])
- reindention of a switch-case block
- spaces to tabs
Signed-off-by: NMatthias Beyer <mail@beyermatthias.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

These aren't necessary after switch and if blocks.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

usb_disconnect() no longer acquires usb_bus_list_lock, so update its
comment to that effect.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>