linux.git/drivers/usb/core/hub.c, branch v3.13

usb: hub: Use correct reset for wedged USB3 devices that are NOTATTACHED

2013-12-05T01:00:43+00:00

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: Julius Werner 
Acked-by: Alan Stern 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

ACPI: Eliminate the DEVICE_ACPI_HANDLE() macro

2013-11-14T22:17:21+00:00

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: Rafael J. Wysocki 
Acked-by: Greg Kroah-Hartman

Merge tag 'for-usb-next-2013-10-17' of git://git.kernel.org/pub/scm/linux/kernel/git/sarah/xhci into usb-next

2013-10-19T21:03:44+00:00

Sarah writes:

xhci: Final patches for 3.13

Hi Greg,

Here's my pull request for usb-next and 3.13.  My xHCI tree is closed
after this point, since I won't be able to run my full tests while I'm in
Scotland.  After Kernel Summit, I'll be on vacation with access to email
from Oct 26th to Nov 6th.

Here's what's in this request:

 - Patches to fix USB 2.0 Link PM issues that cause USB 3.0 devices to not
   enumerate or misbehave when plugged into a USB 2.0 port.  Those are
   marked for stable.

 - A msec vs jiffies bug fix by xiao jin, which results in fairly harmless
   behavior, and thus isn't marked for stable.

 - Xenia's patches to refactor the xHCI command handling code, which makes
   it much more readable and consistent.

 - Misc cleanup patches, one by Sachin Kamat and three from Dan Williams.

Here's what's not in this request:

 - Dan's two patches to allow the xHCI host to use the "Windows" or "new"
   enumeration scheme.  I did not have time to test those, and I want to
   run them with as many USB devices as I can get a hold of.  That will
   have to wait for 3.14.

 - Xenia's patches to remove xhci_readl in favor of readl.  I'll queue
   those for 3.14 after I test them.

 - The xHCI streams update, UAS fixes, and usbfs streams support.  I'm not
   comfortable with changes and fixes to that patchset coming in this late.
   I would rather wait for 3.14 and be really sure the streams support is
   stable before we add new userspace API and remove CONFIG_BROKEN from the
   uas driver.

 - Julius' patch to clear the port reset bit on hub resume that came in
   a couple days ago.  It looks harmless, but I would rather take the time
   to test and queue it for usb-linus and the stable trees once 3.13-rc1
   is out.

Sarah Sharp

usb: hub_activate kill an 'else'

2013-10-16T22:48:30+00:00

Remove a few extra lines and make it clear that all implementations
disable the port by sharing the same line of code.

Acked-by: Alan Stern 
Signed-off-by: Dan Williams 
Signed-off-by: Sarah Sharp

usb: hub: Clear Port Reset Change during init/resume

2013-10-16T20:44:54+00:00

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: Julius Werner 
Acked-by: Alan Stern 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

xhci: Enable LPM support only for hardwired or BESL devices

2013-10-16T19:24:20+00:00

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 a558ccdcc71c7770c5e80c926a31cfe8a3892a09 "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: Mathias Nyman 
Signed-off-by: Sarah Sharp 
Cc: stable@vger.kernel.org

usb: Don't enable USB 2.0 Link PM by default.

2013-10-16T19:24:19+00:00

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 a558ccdcc71c7770c5e80c926a31cfe8a3892a09 "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: Sarah Sharp 
Cc: stable@vger.kernel.org

usb: Disable USB 2.0 Link PM before device reset.

2013-10-16T19:24:17+00:00

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 65580b4321eb36f16ae8b5987bfa1bb948fc5112 "xHCI: set USB2
hardware LPM".  That was the first commit to enable USB 2.0
hardware-driven Link Power Management.

Signed-off-by: Sarah Sharp 
Cc: stable@vger.kernel.org

drivers: usb: core: hub.c: Comments shouldnt be C99 // comment style

2013-10-12T00:06:12+00:00

Signed-off-by: Matthias Beyer 
Signed-off-by: Greg Kroah-Hartman

drivers: usb: core: {file,hub,sysfs,usb}.c: Whitespace fixes

2013-10-12T00:02:37+00:00

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: Matthias Beyer 
Signed-off-by: Greg Kroah-Hartman